The Pd-PCy3 (Cy = cyclohexyl) system effectively catalyzed hydrosilylation polymerization of dihydrosilanes with p- or m-diethynylbenzene to give silylene-divinylene polymers with Ph, Me, and/or vinyl substituents at the silicon atoms. The resulting polymers showed characteristic absorption and fluorescence spectra in ultraviolet to visible region. p-Phenylene polymers displayed lambda(max) peaks in longer wavelength region than the corresponding m-phenylene polymers. In TGA, the 5% weight loss temperatures (Td(5)) ranged from 436 to 501 degreesC, indicating rather high thermal stability of these polymers. Vinyl group-containing polymers exhibited higher Td(5) values and char yields than other polymers. (C) 2003 Published by Elsevier Ltd.