diff --git a/src/ome_types/model/_shape_union.py b/src/ome_types/model/_shape_union.py
index 289ff442..550c345a 100644
--- a/src/ome_types/model/_shape_union.py
+++ b/src/ome_types/model/_shape_union.py
@@ -55,8 +55,9 @@ class ShapeUnion(OMEType, RootModel, UserSequence[ShapeType]):  # type: ignore[m
             default_factory=list,
             json_schema_extra={
                 "type": "Elements",
-                "choices": tuple(  # type: ignore[dict-item]
-                    {"name": kind.title(), "type": cls} for kind, cls in _KINDS.items()
+                "choices": tuple(
+                    (("name", kind.title()), ("type", cls))
+                    for kind, cls in _KINDS.items()
                 ),
             },
         )
@@ -120,7 +121,8 @@ class ShapeUnion(OMEType, UserSequence[ShapeType]):  # type: ignore
             metadata={  # type: ignore[call-arg]
                 "type": "Elements",
                 "choices": tuple(
-                    {"name": kind.title(), "type": cls} for kind, cls in _KINDS.items()
+                    (("name", kind.title()), ("type", cls))
+                    for kind, cls in _KINDS.items()
                 ),
             },
         )
diff --git a/src/ome_types/model/_structured_annotations.py b/src/ome_types/model/_structured_annotations.py
index ca6f056a..92ecacdc 100644
--- a/src/ome_types/model/_structured_annotations.py
+++ b/src/ome_types/model/_structured_annotations.py
@@ -64,8 +64,8 @@ class StructuredAnnotationList(OMEType, RootModel, UserSequence[Annotation]):  #
             default_factory=list,
             json_schema_extra={
                 "type": "Elements",
-                "choices": tuple(  # type: ignore[dict-item]
-                    {"name": cls.__name__, "type": cls} for cls in AnnotationTypes
+                "choices": tuple(
+                    (("name", cls.__name__), ("type", cls)) for cls in AnnotationTypes
                 ),
             },
         )
@@ -127,7 +127,7 @@ class StructuredAnnotationList(OMEType, UserSequence[Annotation]):  # type: igno
             metadata={  # type: ignore[call-arg]
                 "type": "Elements",
                 "choices": tuple(
-                    {"name": cls.__name__, "type": cls} for cls in AnnotationTypes
+                    (("name", cls.__name__), ("type", cls)) for cls in AnnotationTypes
                 ),
             },
         )
diff --git a/src/xsdata_pydantic_basemodel/pydantic_compat.py b/src/xsdata_pydantic_basemodel/pydantic_compat.py
index 7bf4df3e..94e242d0 100644
--- a/src/xsdata_pydantic_basemodel/pydantic_compat.py
+++ b/src/xsdata_pydantic_basemodel/pydantic_compat.py
@@ -54,6 +54,19 @@ def _pydantic_field_to_dataclass_field(name: str, pydantic_field: FieldInfo) ->
 
     metadata = _get_metadata(pydantic_field)
 
+    # HACK
+    # see https://github.com/tlambert03/ome-types/pull/235 for description of problem
+    # This is a hack to get around the fact that xsdata requires Element choices
+    # to be added to the Field metadata as `choices: List[dict]` ... but pydantic
+    # requires that everything in a Field be hashable (if you want to cast the model
+    # to a JSON schema), and `dict` is not hashable. So here, when we're converting
+    # a pydantic Field to a dataclass Field for xsdata to consume, we cast all items
+    # in the `choices` list to `dict` (which is hashable).
+    # Then, in our source code, we declare choices as tuple[tuple[str, str], ...]
+    # which IS hashable.
+    if "choices" in metadata:
+        metadata["choices"] = [dict(choice) for choice in metadata["choices"]]
+
     dataclass_field = field(  # type: ignore
         default=default, default_factory=default_factory, metadata=metadata
     )