diff --git a/libs/langchain/langchain/schema/runnable.py b/libs/langchain/langchain/schema/runnable.py
index f13786565c..a3d3f80f3e 100644
--- a/libs/langchain/langchain/schema/runnable.py
+++ b/libs/langchain/langchain/schema/runnable.py
@@ -214,7 +214,7 @@ class RunnableSequence(Serializable, Runnable[Input, Output]):
         if isinstance(other, RunnableSequence):
             return RunnableSequence(
                 first=self.first,
-                middle=self.middle + [self.last] + other.middle,
+                middle=self.middle + [self.last] + [other.first] + other.middle,
                 last=other.last,
             )
         else:
@@ -235,7 +235,7 @@ class RunnableSequence(Serializable, Runnable[Input, Output]):
         if isinstance(other, RunnableSequence):
             return RunnableSequence(
                 first=other.first,
-                middle=other.middle + [other.last] + self.middle,
+                middle=other.middle + [other.last] + [self.first] + self.middle,
                 last=self.last,
             )
         else:
diff --git a/libs/langchain/tests/unit_tests/schema/__snapshots__/test_runnable.ambr b/libs/langchain/tests/unit_tests/schema/__snapshots__/test_runnable.ambr
index 5f53c2146e..ed36ee3d9b 100644
--- a/libs/langchain/tests/unit_tests/schema/__snapshots__/test_runnable.ambr
+++ b/libs/langchain/tests/unit_tests/schema/__snapshots__/test_runnable.ambr
@@ -1,4 +1,455 @@
 # serializer version: 1
+# name: test_combining_sequences
+  '''
+  {
+    "lc": 1,
+    "type": "constructor",
+    "id": [
+      "langchain",
+      "schema",
+      "runnable",
+      "RunnableSequence"
+    ],
+    "kwargs": {
+      "first": {
+        "lc": 1,
+        "type": "constructor",
+        "id": [
+          "langchain",
+          "prompts",
+          "chat",
+          "ChatPromptTemplate"
+        ],
+        "kwargs": {
+          "messages": [
+            {
+              "lc": 1,
+              "type": "constructor",
+              "id": [
+                "langchain",
+                "prompts",
+                "chat",
+                "SystemMessagePromptTemplate"
+              ],
+              "kwargs": {
+                "prompt": {
+                  "lc": 1,
+                  "type": "constructor",
+                  "id": [
+                    "langchain",
+                    "prompts",
+                    "prompt",
+                    "PromptTemplate"
+                  ],
+                  "kwargs": {
+                    "input_variables": [],
+                    "template": "You are a nice assistant.",
+                    "template_format": "f-string",
+                    "partial_variables": {}
+                  }
+                }
+              }
+            },
+            {
+              "lc": 1,
+              "type": "constructor",
+              "id": [
+                "langchain",
+                "prompts",
+                "chat",
+                "HumanMessagePromptTemplate"
+              ],
+              "kwargs": {
+                "prompt": {
+                  "lc": 1,
+                  "type": "constructor",
+                  "id": [
+                    "langchain",
+                    "prompts",
+                    "prompt",
+                    "PromptTemplate"
+                  ],
+                  "kwargs": {
+                    "input_variables": [
+                      "question"
+                    ],
+                    "template": "{question}",
+                    "template_format": "f-string",
+                    "partial_variables": {}
+                  }
+                }
+              }
+            }
+          ]
+        }
+      },
+      "middle": [
+        {
+          "lc": 1,
+          "type": "not_implemented",
+          "id": [
+            "langchain",
+            "chat_models",
+            "fake",
+            "FakeListChatModel"
+          ]
+        }
+      ],
+      "last": {
+        "lc": 1,
+        "type": "constructor",
+        "id": [
+          "langchain",
+          "output_parsers",
+          "list",
+          "CommaSeparatedListOutputParser"
+        ],
+        "kwargs": {}
+      }
+    }
+  }
+  '''
+# ---
+# name: test_combining_sequences.1
+  '''
+  {
+    "lc": 1,
+    "type": "constructor",
+    "id": [
+      "langchain",
+      "schema",
+      "runnable",
+      "RunnableSequence"
+    ],
+    "kwargs": {
+      "first": {
+        "lc": 1,
+        "type": "not_implemented",
+        "id": [
+          "langchain",
+          "schema",
+          "runnable",
+          "RunnableLambda"
+        ]
+      },
+      "middle": [
+        {
+          "lc": 1,
+          "type": "constructor",
+          "id": [
+            "langchain",
+            "prompts",
+            "chat",
+            "ChatPromptTemplate"
+          ],
+          "kwargs": {
+            "messages": [
+              {
+                "lc": 1,
+                "type": "constructor",
+                "id": [
+                  "langchain",
+                  "prompts",
+                  "chat",
+                  "SystemMessagePromptTemplate"
+                ],
+                "kwargs": {
+                  "prompt": {
+                    "lc": 1,
+                    "type": "constructor",
+                    "id": [
+                      "langchain",
+                      "prompts",
+                      "prompt",
+                      "PromptTemplate"
+                    ],
+                    "kwargs": {
+                      "input_variables": [],
+                      "template": "You are a nicer assistant.",
+                      "template_format": "f-string",
+                      "partial_variables": {}
+                    }
+                  }
+                }
+              },
+              {
+                "lc": 1,
+                "type": "constructor",
+                "id": [
+                  "langchain",
+                  "prompts",
+                  "chat",
+                  "HumanMessagePromptTemplate"
+                ],
+                "kwargs": {
+                  "prompt": {
+                    "lc": 1,
+                    "type": "constructor",
+                    "id": [
+                      "langchain",
+                      "prompts",
+                      "prompt",
+                      "PromptTemplate"
+                    ],
+                    "kwargs": {
+                      "input_variables": [
+                        "question"
+                      ],
+                      "template": "{question}",
+                      "template_format": "f-string",
+                      "partial_variables": {}
+                    }
+                  }
+                }
+              }
+            ]
+          }
+        },
+        {
+          "lc": 1,
+          "type": "not_implemented",
+          "id": [
+            "langchain",
+            "chat_models",
+            "fake",
+            "FakeListChatModel"
+          ]
+        }
+      ],
+      "last": {
+        "lc": 1,
+        "type": "constructor",
+        "id": [
+          "langchain",
+          "output_parsers",
+          "list",
+          "CommaSeparatedListOutputParser"
+        ],
+        "kwargs": {}
+      }
+    }
+  }
+  '''
+# ---
+# name: test_combining_sequences.2
+  '''
+  {
+    "lc": 1,
+    "type": "constructor",
+    "id": [
+      "langchain",
+      "schema",
+      "runnable",
+      "RunnableSequence"
+    ],
+    "kwargs": {
+      "first": {
+        "lc": 1,
+        "type": "constructor",
+        "id": [
+          "langchain",
+          "prompts",
+          "chat",
+          "ChatPromptTemplate"
+        ],
+        "kwargs": {
+          "messages": [
+            {
+              "lc": 1,
+              "type": "constructor",
+              "id": [
+                "langchain",
+                "prompts",
+                "chat",
+                "SystemMessagePromptTemplate"
+              ],
+              "kwargs": {
+                "prompt": {
+                  "lc": 1,
+                  "type": "constructor",
+                  "id": [
+                    "langchain",
+                    "prompts",
+                    "prompt",
+                    "PromptTemplate"
+                  ],
+                  "kwargs": {
+                    "input_variables": [],
+                    "template": "You are a nice assistant.",
+                    "template_format": "f-string",
+                    "partial_variables": {}
+                  }
+                }
+              }
+            },
+            {
+              "lc": 1,
+              "type": "constructor",
+              "id": [
+                "langchain",
+                "prompts",
+                "chat",
+                "HumanMessagePromptTemplate"
+              ],
+              "kwargs": {
+                "prompt": {
+                  "lc": 1,
+                  "type": "constructor",
+                  "id": [
+                    "langchain",
+                    "prompts",
+                    "prompt",
+                    "PromptTemplate"
+                  ],
+                  "kwargs": {
+                    "input_variables": [
+                      "question"
+                    ],
+                    "template": "{question}",
+                    "template_format": "f-string",
+                    "partial_variables": {}
+                  }
+                }
+              }
+            }
+          ]
+        }
+      },
+      "middle": [
+        {
+          "lc": 1,
+          "type": "not_implemented",
+          "id": [
+            "langchain",
+            "chat_models",
+            "fake",
+            "FakeListChatModel"
+          ]
+        },
+        {
+          "lc": 1,
+          "type": "constructor",
+          "id": [
+            "langchain",
+            "output_parsers",
+            "list",
+            "CommaSeparatedListOutputParser"
+          ],
+          "kwargs": {}
+        },
+        {
+          "lc": 1,
+          "type": "not_implemented",
+          "id": [
+            "langchain",
+            "schema",
+            "runnable",
+            "RunnableLambda"
+          ]
+        },
+        {
+          "lc": 1,
+          "type": "constructor",
+          "id": [
+            "langchain",
+            "prompts",
+            "chat",
+            "ChatPromptTemplate"
+          ],
+          "kwargs": {
+            "messages": [
+              {
+                "lc": 1,
+                "type": "constructor",
+                "id": [
+                  "langchain",
+                  "prompts",
+                  "chat",
+                  "SystemMessagePromptTemplate"
+                ],
+                "kwargs": {
+                  "prompt": {
+                    "lc": 1,
+                    "type": "constructor",
+                    "id": [
+                      "langchain",
+                      "prompts",
+                      "prompt",
+                      "PromptTemplate"
+                    ],
+                    "kwargs": {
+                      "input_variables": [],
+                      "template": "You are a nicer assistant.",
+                      "template_format": "f-string",
+                      "partial_variables": {}
+                    }
+                  }
+                }
+              },
+              {
+                "lc": 1,
+                "type": "constructor",
+                "id": [
+                  "langchain",
+                  "prompts",
+                  "chat",
+                  "HumanMessagePromptTemplate"
+                ],
+                "kwargs": {
+                  "prompt": {
+                    "lc": 1,
+                    "type": "constructor",
+                    "id": [
+                      "langchain",
+                      "prompts",
+                      "prompt",
+                      "PromptTemplate"
+                    ],
+                    "kwargs": {
+                      "input_variables": [
+                        "question"
+                      ],
+                      "template": "{question}",
+                      "template_format": "f-string",
+                      "partial_variables": {}
+                    }
+                  }
+                }
+              }
+            ]
+          }
+        },
+        {
+          "lc": 1,
+          "type": "not_implemented",
+          "id": [
+            "langchain",
+            "chat_models",
+            "fake",
+            "FakeListChatModel"
+          ]
+        }
+      ],
+      "last": {
+        "lc": 1,
+        "type": "constructor",
+        "id": [
+          "langchain",
+          "output_parsers",
+          "list",
+          "CommaSeparatedListOutputParser"
+        ],
+        "kwargs": {}
+      }
+    }
+  }
+  '''
+# ---
+# name: test_combining_sequences.3
+  list([
+    Run(id=UUID('00000000-0000-4000-8000-000000000000'), name='RunnableSequence', start_time=FakeDatetime(2023, 1, 1, 0, 0), run_type=<RunTypeEnum.chain: 'chain'>, end_time=FakeDatetime(2023, 1, 1, 0, 0), extra={}, error=None, serialized={'lc': 1, 'type': 'constructor', 'id': ['langchain', 'schema', 'runnable', 'RunnableSequence'], 'kwargs': {'first': {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'chat', 'ChatPromptTemplate'], 'kwargs': {'messages': [{'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'chat', 'SystemMessagePromptTemplate'], 'kwargs': {'prompt': {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'prompt', 'PromptTemplate'], 'kwargs': {'input_variables': [], 'template': 'You are a nice assistant.', 'template_format': 'f-string', 'partial_variables': {}}}}}, {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'chat', 'HumanMessagePromptTemplate'], 'kwargs': {'prompt': {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'prompt', 'PromptTemplate'], 'kwargs': {'input_variables': ['question'], 'template': '{question}', 'template_format': 'f-string', 'partial_variables': {}}}}}]}}, 'middle': [{'lc': 1, 'type': 'not_implemented', 'id': ['langchain', 'chat_models', 'fake', 'FakeListChatModel']}, {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'output_parsers', 'list', 'CommaSeparatedListOutputParser'], 'kwargs': {}}, {'lc': 1, 'type': 'not_implemented', 'id': ['langchain', 'schema', 'runnable', 'RunnableLambda']}, {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'chat', 'ChatPromptTemplate'], 'kwargs': {'messages': [{'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'chat', 'SystemMessagePromptTemplate'], 'kwargs': {'prompt': {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'prompt', 'PromptTemplate'], 'kwargs': {'input_variables': [], 'template': 'You are a nicer assistant.', 'template_format': 'f-string', 'partial_variables': {}}}}}, {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'chat', 'HumanMessagePromptTemplate'], 'kwargs': {'prompt': {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'prompt', 'PromptTemplate'], 'kwargs': {'input_variables': ['question'], 'template': '{question}', 'template_format': 'f-string', 'partial_variables': {}}}}}]}}, {'lc': 1, 'type': 'not_implemented', 'id': ['langchain', 'chat_models', 'fake', 'FakeListChatModel']}], 'last': {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'output_parsers', 'list', 'CommaSeparatedListOutputParser'], 'kwargs': {}}}}, events=[{'name': 'start', 'time': FakeDatetime(2023, 1, 1, 0, 0)}, {'name': 'end', 'time': FakeDatetime(2023, 1, 1, 0, 0)}], inputs={'question': 'What is your name?'}, outputs={'output': ['baz', 'qux']}, reference_example_id=None, parent_run_id=None, tags=[], execution_order=1, child_execution_order=8, child_runs=[Run(id=UUID('00000000-0000-4000-8000-000000000001'), name='ChatPromptTemplate', start_time=FakeDatetime(2023, 1, 1, 0, 0), run_type=<RunTypeEnum.chain: 'chain'>, end_time=FakeDatetime(2023, 1, 1, 0, 0), extra={}, error=None, serialized={'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'chat', 'ChatPromptTemplate'], 'kwargs': {'messages': [{'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'chat', 'SystemMessagePromptTemplate'], 'kwargs': {'prompt': {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'prompt', 'PromptTemplate'], 'kwargs': {'input_variables': [], 'template': 'You are a nice assistant.', 'template_format': 'f-string', 'partial_variables': {}}}}}, {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'chat', 'HumanMessagePromptTemplate'], 'kwargs': {'prompt': {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'prompt', 'PromptTemplate'], 'kwargs': {'input_variables': ['question'], 'template': '{question}', 'template_format': 'f-string', 'partial_variables': {}}}}}]}}, events=[{'name': 'start', 'time': FakeDatetime(2023, 1, 1, 0, 0)}, {'name': 'end', 'time': FakeDatetime(2023, 1, 1, 0, 0)}], inputs={'question': 'What is your name?'}, outputs={'output': ChatPromptValue(messages=[SystemMessage(content='You are a nice assistant.', additional_kwargs={}), HumanMessage(content='What is your name?', additional_kwargs={}, example=False)])}, reference_example_id=None, parent_run_id=UUID('00000000-0000-4000-8000-000000000000'), tags=[], execution_order=2, child_execution_order=2, child_runs=[]), Run(id=UUID('00000000-0000-4000-8000-000000000002'), name='FakeListChatModel', start_time=FakeDatetime(2023, 1, 1, 0, 0), run_type=<RunTypeEnum.llm: 'llm'>, end_time=FakeDatetime(2023, 1, 1, 0, 0), extra={'invocation_params': {'responses': ['foo, bar'], '_type': 'fake-list-chat-model', 'stop': None}, 'options': {'stop': None}}, error=None, serialized={'lc': 1, 'type': 'not_implemented', 'id': ['langchain', 'chat_models', 'fake', 'FakeListChatModel']}, events=[{'name': 'start', 'time': FakeDatetime(2023, 1, 1, 0, 0)}, {'name': 'end', 'time': FakeDatetime(2023, 1, 1, 0, 0)}], inputs={'prompts': ['System: You are a nice assistant.\nHuman: What is your name?']}, outputs={'generations': [[{'text': 'foo, bar', 'generation_info': None, 'message': {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'schema', 'messages', 'AIMessage'], 'kwargs': {'content': 'foo, bar'}}}]], 'llm_output': None, 'run': None}, reference_example_id=None, parent_run_id=UUID('00000000-0000-4000-8000-000000000000'), tags=[], execution_order=3, child_execution_order=3, child_runs=[]), Run(id=UUID('00000000-0000-4000-8000-000000000003'), name='CommaSeparatedListOutputParser', start_time=FakeDatetime(2023, 1, 1, 0, 0), run_type=<RunTypeEnum.chain: 'chain'>, end_time=FakeDatetime(2023, 1, 1, 0, 0), extra={}, error=None, serialized={'lc': 1, 'type': 'constructor', 'id': ['langchain', 'output_parsers', 'list', 'CommaSeparatedListOutputParser'], 'kwargs': {}}, events=[{'name': 'start', 'time': FakeDatetime(2023, 1, 1, 0, 0)}, {'name': 'end', 'time': FakeDatetime(2023, 1, 1, 0, 0)}], inputs={'input': AIMessage(content='foo, bar', additional_kwargs={}, example=False)}, outputs={'output': ['foo', 'bar']}, reference_example_id=None, parent_run_id=UUID('00000000-0000-4000-8000-000000000000'), tags=[], execution_order=4, child_execution_order=4, child_runs=[]), Run(id=UUID('00000000-0000-4000-8000-000000000004'), name='RunnableLambda', start_time=FakeDatetime(2023, 1, 1, 0, 0), run_type=<RunTypeEnum.chain: 'chain'>, end_time=FakeDatetime(2023, 1, 1, 0, 0), extra={}, error=None, serialized={'lc': 1, 'type': 'not_implemented', 'id': ['langchain', 'schema', 'runnable', 'RunnableLambda']}, events=[{'name': 'start', 'time': FakeDatetime(2023, 1, 1, 0, 0)}, {'name': 'end', 'time': FakeDatetime(2023, 1, 1, 0, 0)}], inputs={'input': ['foo', 'bar']}, outputs={'question': 'foobar'}, reference_example_id=None, parent_run_id=UUID('00000000-0000-4000-8000-000000000000'), tags=[], execution_order=5, child_execution_order=5, child_runs=[]), Run(id=UUID('00000000-0000-4000-8000-000000000005'), name='ChatPromptTemplate', start_time=FakeDatetime(2023, 1, 1, 0, 0), run_type=<RunTypeEnum.chain: 'chain'>, end_time=FakeDatetime(2023, 1, 1, 0, 0), extra={}, error=None, serialized={'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'chat', 'ChatPromptTemplate'], 'kwargs': {'messages': [{'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'chat', 'SystemMessagePromptTemplate'], 'kwargs': {'prompt': {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'prompt', 'PromptTemplate'], 'kwargs': {'input_variables': [], 'template': 'You are a nicer assistant.', 'template_format': 'f-string', 'partial_variables': {}}}}}, {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'chat', 'HumanMessagePromptTemplate'], 'kwargs': {'prompt': {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'prompts', 'prompt', 'PromptTemplate'], 'kwargs': {'input_variables': ['question'], 'template': '{question}', 'template_format': 'f-string', 'partial_variables': {}}}}}]}}, events=[{'name': 'start', 'time': FakeDatetime(2023, 1, 1, 0, 0)}, {'name': 'end', 'time': FakeDatetime(2023, 1, 1, 0, 0)}], inputs={'question': 'foobar'}, outputs={'output': ChatPromptValue(messages=[SystemMessage(content='You are a nicer assistant.', additional_kwargs={}), HumanMessage(content='foobar', additional_kwargs={}, example=False)])}, reference_example_id=None, parent_run_id=UUID('00000000-0000-4000-8000-000000000000'), tags=[], execution_order=6, child_execution_order=6, child_runs=[]), Run(id=UUID('00000000-0000-4000-8000-000000000006'), name='FakeListChatModel', start_time=FakeDatetime(2023, 1, 1, 0, 0), run_type=<RunTypeEnum.llm: 'llm'>, end_time=FakeDatetime(2023, 1, 1, 0, 0), extra={'invocation_params': {'responses': ['baz, qux'], '_type': 'fake-list-chat-model', 'stop': None}, 'options': {'stop': None}}, error=None, serialized={'lc': 1, 'type': 'not_implemented', 'id': ['langchain', 'chat_models', 'fake', 'FakeListChatModel']}, events=[{'name': 'start', 'time': FakeDatetime(2023, 1, 1, 0, 0)}, {'name': 'end', 'time': FakeDatetime(2023, 1, 1, 0, 0)}], inputs={'prompts': ['System: You are a nicer assistant.\nHuman: foobar']}, outputs={'generations': [[{'text': 'baz, qux', 'generation_info': None, 'message': {'lc': 1, 'type': 'constructor', 'id': ['langchain', 'schema', 'messages', 'AIMessage'], 'kwargs': {'content': 'baz, qux'}}}]], 'llm_output': None, 'run': None}, reference_example_id=None, parent_run_id=UUID('00000000-0000-4000-8000-000000000000'), tags=[], execution_order=7, child_execution_order=7, child_runs=[]), Run(id=UUID('00000000-0000-4000-8000-000000000007'), name='CommaSeparatedListOutputParser', start_time=FakeDatetime(2023, 1, 1, 0, 0), run_type=<RunTypeEnum.chain: 'chain'>, end_time=FakeDatetime(2023, 1, 1, 0, 0), extra={}, error=None, serialized={'lc': 1, 'type': 'constructor', 'id': ['langchain', 'output_parsers', 'list', 'CommaSeparatedListOutputParser'], 'kwargs': {}}, events=[{'name': 'start', 'time': FakeDatetime(2023, 1, 1, 0, 0)}, {'name': 'end', 'time': FakeDatetime(2023, 1, 1, 0, 0)}], inputs={'input': AIMessage(content='baz, qux', additional_kwargs={}, example=False)}, outputs={'output': ['baz', 'qux']}, reference_example_id=None, parent_run_id=UUID('00000000-0000-4000-8000-000000000000'), tags=[], execution_order=8, child_execution_order=8, child_runs=[])]),
+  ])
+# ---
 # name: test_prompt_with_chat_model
   '''
   {
diff --git a/libs/langchain/tests/unit_tests/schema/test_runnable.py b/libs/langchain/tests/unit_tests/schema/test_runnable.py
index d912e18982..3b73658886 100644
--- a/libs/langchain/tests/unit_tests/schema/test_runnable.py
+++ b/libs/langchain/tests/unit_tests/schema/test_runnable.py
@@ -440,6 +440,64 @@ def test_prompt_with_chat_model_and_parser(
     assert tracer.runs == snapshot
 
 
+@freeze_time("2023-01-01")
+def test_combining_sequences(
+    mocker: MockerFixture, snapshot: SnapshotAssertion
+) -> None:
+    prompt = (
+        SystemMessagePromptTemplate.from_template("You are a nice assistant.")
+        + "{question}"
+    )
+    chat = FakeListChatModel(responses=["foo, bar"])
+    parser = CommaSeparatedListOutputParser()
+
+    chain = prompt | chat | parser
+
+    assert isinstance(chain, RunnableSequence)
+    assert chain.first == prompt
+    assert chain.middle == [chat]
+    assert chain.last == parser
+    assert dumps(chain, pretty=True) == snapshot
+
+    prompt2 = (
+        SystemMessagePromptTemplate.from_template("You are a nicer assistant.")
+        + "{question}"
+    )
+    chat2 = FakeListChatModel(responses=["baz, qux"])
+    parser2 = CommaSeparatedListOutputParser()
+    input_formatter: RunnableLambda[List[str], Dict[str, Any]] = RunnableLambda(
+        lambda x: {"question": x[0] + x[1]}
+    )
+
+    chain2 = input_formatter | prompt2 | chat2 | parser2
+
+    assert isinstance(chain, RunnableSequence)
+    assert chain2.first == input_formatter
+    assert chain2.middle == [prompt2, chat2]
+    assert chain2.last == parser2
+    assert dumps(chain2, pretty=True) == snapshot
+
+    combined_chain = chain | chain2
+
+    assert combined_chain.first == prompt
+    assert combined_chain.middle == [
+        chat,
+        parser,
+        input_formatter,
+        prompt2,
+        chat2,
+    ]
+    assert combined_chain.last == parser2
+    assert dumps(combined_chain, pretty=True) == snapshot
+
+    # Test invoke
+    tracer = FakeTracer()
+    assert combined_chain.invoke(
+        {"question": "What is your name?"}, dict(callbacks=[tracer])
+    ) == ["baz", "qux"]
+    assert tracer.runs == snapshot
+
+
 @freeze_time("2023-01-01")
 def test_seq_dict_prompt_llm(
     mocker: MockerFixture, snapshot: SnapshotAssertion