In this study, we synthesized polyphosphates with reactive pendant chloromethyl groups by an addition reaction of the diglycidyl ether of bisphenol-S (bisphenol-S epoxy, BPSE) with aryl phosphorodichloridates. The polyphosphates obtained were characterized by IR, H-1 NMR spectra, elemental analysis, TGA, DSC, X-ray diffraction, and molar mass measurement. The polyaddition proceeded very smoothly in aromatic solvents catalyzed by quaternary ammonium or phosphonium salts such as tetrabutylammonium bromide and tetrabutylphosphonium bromide to produce a polymer having a high molecular weight, Polymer B, containing a bromine atom in the phenyl ring side chain, has the higher T-g value (T-g = 58 degrees C) than the polyphosphate derived from phenoxy dichlorophosphate (PDCP). Polymer A derived from PDCP begins to lose 10% of its mass at 278 degrees C, and the mass percentage remaining at 700 degrees C is 44% under nitrogen. X-ray diffraction patterns revealed that all the subsequent polyphosphates are amorphous.