Polymerization of p-(dimethylsilyl)phenylacetylene in toluene at 25 and 80degreesC with RhI(PPh3)(3) catalyst afforded highly regio- and stereoregular poly(dimethylsilylene1,4-phenylenevinylene)s [cis- and trans-poly(1a)s] containing 98% cis- and 99% transvinylene moieties, respectively. The trans-type polymers exhibited redshifts and hyperchromic effects in the ultraviolet-mvisible spectrum as compared with the cis-type counterparts. Photoirradiation of cis- and trans-poly(la)s gave cis-rich mixtures at equilibrium states. The trans and cis polymers exhibited different emission properties, for example-trans polymer, emissn lambda(max) = 400 nm, quantum yield: 3.4 x 10(-3) and cis polymer, emissn lambda(max) = 380 nm, quantum yield: 1.5 x 10(-3). Besides poly(1a), poly(dimethylsilylenearylenevinylene)s containing biphenylene and phenylenesilylenephenylene units [poly(3)] were prepared. The extent of conjugation in these polymers decreased in the orders of biphenylene > phenylene > phenylenesilylenephenylene as well as trans-vinylene > cis-Vinylene. The quantum yield of the trans-rich polymer with biphenylene moiety was fairly large and 0.15. Polyaddition of 1,4-bis(dimethylsilyl)benzene and three types of diethynylarenes (4,4'-diethynylbiphenyl, 2,7-diethynylfluorene, and 2,6-diethynylnaphthalene) catalyzed by RhI(PPh3)(3) provided novel regio- and stereoregular polymers [poly(6)]. These polymers displayed blue light emission with high quantum yields (4-81%). (C) 2003 Wiley Periodicals, Inc.