This article overviews the new aspects of transition metal catalysts for polymerization of substituted acetylene monomers. The activity of rhodium-based catalysts is enhanced by introducing a strongly π-acidic diene ligand, tetrafluorobenzobarrelene (tfb). Precise control of polymerization of phenylacetylenes is achieved by two types of rhodium catalysts bearing tfb. The activity of zwitterionic rhodium-type catalyst is also intensified by the introduction of tfb, which achieves a higher monomer consumption rate than that with the conventional rhodium catalyst. Disubstituted acetylenes with polar functional groups are polymerized by well-defined ruthenium carbene catalyst. Phenylacetylenes having a coordinative substituent at the ortho position on its aromatic ring are efficiently polymerized by the ruthenium carbene catalyst to give the corresponding polymers in high yields.