In this study, a new poly(silyl ether) with reactive pendant chloromethyl groups was synthesized by an addition reaction between dichlorodiphenylsilane (CPS) and the diglycidyl ether of bisphenol-S (bisphenol-S epoxy). The polyaddition proceeded very smoothly and regioselectively in toluene catalysed by quaternary ammonium or phosphonium salts such as tetrabutylammonium bromide, tetrabutylammonium fluoride and tetrabutylphosphonium bromide to produce a polymer with high molecular weight. The polyaddition also proceeded using triphenylphosphine as a catalyst to afford the poly(silyl ether), but with low molecular weight. On the other hand, the reaction did not occur without a catalyst under the same reaction conditions. Also, the nature of the catalyst and the reaction solvent influenced the polymer’s yields and molecular weights. The glass transition temperature of poly(silyl ether) was 68 degrees C and the X-ray diffraction pattern revealed that the polymer was semi-crystalline. Furthermore, experimental results indicated that the subsequent poly(silyl ether) based on bisphenol-S with reactive pendant chloromethyl groups exhibited excellent solubility in common organic solvents.