The polyaddition of 1,4-bis [(3-ethyl-3-oxetanyl)methoxymethyl] benzene (BEOB) with 3,3',5,5'-tetrachlorobisphenol A (TCBPA) was examined with or without catalysts. High molecular weight polymer (polymers 1) (M-n = 13,600) with pendant primary hydroxyl groups was obtained in a 99% yield without any gel products when the reaction was performed with 5 mol % of tetraphenylphosphonium bromide as a catalyst in NMP at 160 degrees C for 96 h. However, when the reaction was carried out without a catalyst under the same conditions, a low molecular weight polymer (M-n = 3200) was obtained in a 51% yield. The structure of the resulting polymer was confirmed by IR, H-1-NMR, and C-13-NMR spectra. In this reaction system, it was also found that tetraphenylphosphonium iodide and crown ether complexes such as 18-crown-6 (18-C-6)/KBr and 18-C-6/KI have high catalytic activity. Polyadditions of 1,4-bis[(3-methyl-3-oxetanyl)methoxymethyl] benzene with TCBPA and BEOB with 3,3',5,5 5'-tetrabromobisphenol-S were also examined, and corresponding polymers (polymers 2 and 3) were obtained in good yields.