Poly(silylenevinylene(bi)phenylenevinylene)s were synthesized by chloro-platinic acid-catalyzed hydrosilylation polymerization between alpha,omega-diethynylarenes and methylphenylsilane or diphenylsilane. The polymer structure was dependent on the substituent size of silane reagent. Poly(silylenevinylenephenylenevinylene)s showed fluorescence emission in the blue region. Optical and thermal properties of the polymers were extensively investigated. (C) 1999 John Wiley & Sons, Inc.