Abstract: | The immobilization of Rh(cod)OCH3]2 (cod = cycloocta‐1,5‐diene) on mesoporous molecular sieves MCM‐41 provides the first inorganic‐type hybrid catalyst, which affords heterogeneous polymerization of phenylacetylene and its ring‐substituted derivatives, – 2‐fluorophenylacetylene, 4‐fluorophenylacetylene, and 4‐pentylphenylacetylene – into readily isolable high‐molecular‐weight (M?w from 50 000 to 180 000) substituted polyvinylenes of high cis‐transoid structure. The activity of this catalyst is compared with that of homogeneous catalyst Rh(cod)OCH3]2. |