diff --git a/grudge/array_context.py b/grudge/array_context.py
index ebdb9eb8..d41cda1b 100644
--- a/grudge/array_context.py
+++ b/grudge/array_context.py
@@ -371,15 +371,15 @@ def _dag_to_compiled_func(self, dict_of_named_arrays,
             name_in_program_to_tags.update(part_prg_name_to_tags)
             name_in_program_to_axes.update(part_prg_name_to_axes)
 
-        from immutabledict import immutabledict
+        from constantdict import constantdict
         return _DistributedCompiledFunction(
                 actx=self.actx,
                 distributed_partition=distributed_partition,
                 part_id_to_prg=part_id_to_prg,
                 input_id_to_name_in_program=input_id_to_name_in_program,
                 output_id_to_name_in_program=output_id_to_name_in_program,
-                name_in_program_to_tags=immutabledict(name_in_program_to_tags),
-                name_in_program_to_axes=immutabledict(name_in_program_to_axes),
+                name_in_program_to_tags=constantdict(name_in_program_to_tags),
+                name_in_program_to_axes=constantdict(name_in_program_to_axes),
                 output_template=output_template)
 
 
diff --git a/pyproject.toml b/pyproject.toml
index f1ff5ceb..258ed86a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -30,7 +30,7 @@ classifiers = [
 ]
 dependencies = [
     "arraycontext>=2021.1",
-    "immutables>=0.19",
+    "constantdict",
     "loopy>=2024.1",
     "meshmode>=2021.2",
     "modepy>=2021.1",