diff --git a/src/oaklib/utilities/lexical/lexical_indexer.py b/src/oaklib/utilities/lexical/lexical_indexer.py
index e3e196524..d46605e1b 100644
--- a/src/oaklib/utilities/lexical/lexical_indexer.py
+++ b/src/oaklib/utilities/lexical/lexical_indexer.py
@@ -247,6 +247,7 @@ def lexical_index_to_sssom(
     ruleset: MappingRuleCollection = None,
     meta: Optional[Dict[str, t.Any]] = None,
     prefix_map: Union[None, Converter, t.Mapping[str, str]] = None,
+    extended_prefix_map: t.Iterable[Dict[str, t.Any]] = None,
     subjects: Collection[CURIE] = None,
     objects: Collection[CURIE] = None,
     symmetric: bool = False,
@@ -265,6 +266,9 @@ def lexical_index_to_sssom(
     :param ensure_strict_prefixes: If true, prefixes & mappings in SSSOM MappingSetDataFrame will be filtred.
     :return: SSSOM MappingSetDataFrame object.
     """
+    if prefix_map and extended_prefix_map:
+        raise ValueError('Can only pass prefix_map or extended_prefix_map, but not both.')
+
     mappings = []
     logging.info("Converting lexical index to SSSOM")
     if subjects:
@@ -275,6 +279,7 @@ def lexical_index_to_sssom(
         symmetric = True
         logging.info("Forcing symmetric comparison")
     logging.info(f"Iterating over {len(lexical_index.groupings)} groupings")
+
     for term, grouping in lexical_index.groupings.items():
         # elements = set([r.element for r in grouping.relationships])
         elementmap = defaultdict(list)
@@ -313,7 +318,9 @@ def lexical_index_to_sssom(
 
     converter = curies.chain(
         [
-            Converter.from_prefix_map((meta or {}).pop(CURIE_MAP, {})),
+            Converter.from_extended_prefix_map(extended_prefix_map) if extended_prefix_map \
+                else Converter.from_prefix_map(prefix_map) if prefix_map \
+                else Converter.from_prefix_map((meta or {}).pop(CURIE_MAP, {})),
             ensure_converter(prefix_map, use_defaults=False),
             oi.converter,
         ]