Cross-dehydrocoupling reactions of (R)-methyl(1-naphthyl)phenylsilane (>99%ee) with (S)-methyl(1-naphthyl)phenylsilanol (>99% ee) proceeded with 82–99% retention of configuration of chiral silicon centres in the presence of various Rh-catalysts. Cross-dehydrocoupling polymerization of 1,3-dimethyl-1,3-diphenyl-1,3-disiloxanediol with 1,3-dihydro-1,3-dimethyl-1,3-diphenyl-1,3-disiloxane gave poly(methylphenylsiloxane) of moderate molecular weight in toluene at 60 °C in the presence of [RhCl(cod)]2 (5.0 mol%) and triethylamine (1.0 equivalent). Assignment of the triad signals of the resulting polymer was made by 1H NMR spectroscopy of the methyl proton (I = 0.04, H = 0.09 and S = 0.14 ppm) and 13C NMR spectroscopy of the ipso carbon of the phenyl group (S = 136.7, H = 136.9, and I = 137.1 ppm). Although the reaction of optically pure (S,S)-1,3-dimethyl-1,3-diphenyl-1,3-disiloxanediol with 1,3-dihydro-1,3-dimethyl-1,3-diphenyl-1,3-disiloxane [(S,S):(S,R):(R,R)] = 84:16:0] gave a poly(methylphenylsiloxane) of rather low molecular weight, its triad tacticity was found to be rich in syndiotacticity (S:H:I = 60:32:8) by 13C NMR spectroscopy. © 2001 Society of Chemical Industry