This article reviews the development of transition metal catalysts for substituted acetylenes. These catalysts enable us to synthesize a wide variety of substituted polyacetylenes, whose molecular weights and polydispersities can be controlled in some cases. Most of the polymers are soluble in common solvents and stable enough in the air unlike non-substituted polyacetylene. They exhibit interesting features and functions including helix formation, high gas permeability, and photoelectronic properties.