diff --git a/rocrate/model/entity.py b/rocrate/model/entity.py
index 22e69a5..fc23ead 100644
--- a/rocrate/model/entity.py
+++ b/rocrate/model/entity.py
@@ -102,6 +102,9 @@ def __setitem__(self, key: str, value):
         if key.startswith("@"):
             raise KeyError(f"cannot set '{key}'")
         values = value if isinstance(value, list) else [value]
+        for v in values:
+            if isinstance(v, dict) and "@id" not in v:
+                raise ValueError(f"no @id in {v}")
         ref_values = [{"@id": _.id} if isinstance(_, Entity) else _ for _ in values]
         self._jsonld[key] = ref_values if isinstance(value, list) else ref_values[0]
 
diff --git a/test/test_model.py b/test/test_model.py
index 4465ece..c452e21 100644
--- a/test/test_model.py
+++ b/test/test_model.py
@@ -363,6 +363,11 @@ def test_entity_as_mapping(tmpdir, helpers):
     }
     crate_dir = tmpdir / "in_crate"
     crate_dir.mkdir()
+    with open(crate_dir / helpers.METADATA_FILE_NAME, "wt") as f:
+        json.dump(metadata, f, indent=4)
+    with pytest.raises(ValueError):  # due to "badProp", which has no "@id"
+        crate = ROCrate(crate_dir)
+    del metadata["@graph"][2]["badProp"]
     with open(crate_dir / helpers.METADATA_FILE_NAME, "wt") as f:
         json.dump(metadata, f, indent=4)
     crate = ROCrate(crate_dir)
@@ -411,6 +416,9 @@ def test_entity_as_mapping(tmpdir, helpers):
         "application/json",
         "https://www.json.org",
     }
+    with pytest.raises(ValueError):
+        correction["badProp"] = {"k": "v"}  # value has no "@id"
+    correction._jsonld["badProp"] = {"k": "v"}  # force set using _jsonld
     with pytest.raises(ValueError):
         correction["badProp"]