diff --git a/pyiron_ontology/parser.py b/pyiron_ontology/parser.py
index 9c39fdf..b5144d7 100644
--- a/pyiron_ontology/parser.py
+++ b/pyiron_ontology/parser.py
@@ -5,6 +5,7 @@
 from rdflib import Graph, Literal, RDF, RDFS, URIRef, OWL, PROV, Namespace
 from pyiron_workflow import NOT_DATA, Workflow, Macro
 from pyiron_workflow.node import Node
+from dataclasses import is_dataclass
 
 
 class PNS:
@@ -63,10 +64,6 @@ def get_inputs_and_outputs(node: Node) -> dict:
     }
 
 
-def _is_semantikon_class(dtype: type) -> bool:
-    return hasattr(dtype, "_is_semantikon_class") and dtype._is_semantikon_class
-
-
 def _translate_has_value(
     graph: Graph,
     label: URIRef,
@@ -78,13 +75,13 @@ def _translate_has_value(
 ) -> Graph:
     tag_uri = URIRef(tag + ".value")
     graph.add((label, PNS.hasValue, tag_uri))
-    if _is_semantikon_class(dtype):
+    if is_dataclass(dtype):
         warnings.warn(
             "semantikon_class is experimental - triples may change in the future",
             FutureWarning,
         )
         for k, v in dtype.__dict__.items():
-            if isinstance(v, type) and _is_semantikon_class(v):
+            if isinstance(v, type) and is_dataclass(v):
                 _translate_has_value(
                     graph=graph,
                     label=label,
diff --git a/tests/unit/test_parser.py b/tests/unit/test_parser.py
index 231fce0..e1e9a34 100644
--- a/tests/unit/test_parser.py
+++ b/tests/unit/test_parser.py
@@ -11,7 +11,6 @@
 )
 from pyiron_workflow import Workflow
 from semantikon.typing import u
-from semantikon.converter import semantikon_class
 from dataclasses import dataclass
 from rdflib import Namespace
 
@@ -223,26 +222,23 @@ def test_parsing_without_running(self):
         )
 
 
-@semantikon_class
 @dataclass
 class Input:
     T: u(float, units="kelvin")
     n: int
-    # This line should be removed with the next version of semantikon
-    _is_semantikon_class = True
 
+    @dataclass
     class parameters:
-        _is_semantikon_class = True
         a: int = 2
 
+    class not_dataclass:
+        b: int = 3
+
 
-@semantikon_class
 @dataclass
 class Output:
     E: u(float, units="electron_volt")
     L: u(float, units="angstrom")
-    # This line should be removed with the next version of semantikon
-    _is_semantikon_class = True
 
 
 @Workflow.wrap.as_function_node
@@ -268,10 +264,14 @@ def test_dataclass(self):
             (URIRef(o_txt), PNS.hasValue, URIRef(f"{o_txt}.E.value")),
         )
         s = graph.serialize(format="turtle")
-        for triple in triples:
-            self.assertEqual(
-                len(list(graph.triples(triple))), 1, msg=f"{triple} not found in {s}"
-            )
+        for ii, triple in enumerate(triples):
+            with self.subTest(i=ii):
+                self.assertEqual(
+                    len(list(graph.triples(triple))),
+                    1,
+                    msg=f"{triple} not found in {s}",
+                )
+        self.assertIsNone(graph.value(URIRef(f"{i_txt}.not_dataclass.b.value")))
 
 
 if __name__ == "__main__":