Poly(phosphonate)s and poly(phosphate)s with reactive pendant chloromethyl groups were synthesized by polyadditions of bisepoxides with phosphonic dichlorides and dichlorophosphates, respectively. The polyaddition of Bisphenol A diglydcidyl ether (BPGE) with phenylphosphonic dichloride (PPDC) occurred without any catalyst at 90 degrees C for 24 h in toluene; however, the yield and molecular weight of the resulting polymer were relatively low. On the other hand, the polyadditions of BPGE with PPDC proceeded very smoothly and regioselectively with high yields (90-96%) to give the polymers with relatively high molecular weights in toluene at 90 degrees C for 24 h when quaternary ammonium or phosphonium salts were used as catalysts. The polyaddition was enhanced by the addition of triethylamine, triphenylphosphine, or crown ether complex; however, the catalytic activities of these compounds were lower than those of quaternary onium salts. Polyadditions of bisepoxides such as BPGE and ethylene glycol diglycidyl ether with certain phosphonic dichlorides and dichlorophosphates also proceeded smoothly and regioselectively to give the corresponding polymers under the same reaction conditions.