The synthesis and self-polyaddition of new monomers, o-, m-, and p-[(3-ethyloxetane-3-yl)metlioxyetliyl]benzoic acid (o-EOMB, m-EOMB, and p-EOMB) containing both oxetanyl groups and carboxyl groups were examined. The reactions of o-EOMB, m-EOMB, and p-EOMB in the presence of tetraphenylphosphonium bromide as a catalyst in o-dichlorobenzene at 150-170 degrees C resulted in self-polyaddition to give the corresponding hetero-telechelic polymers poly(o-EOMB), poly(m-EOMB), and poly(p-EOMB) with M(n)s = 14,500-33,400 in satisfactory yields. The M-n of poly (o-EOMB) decreased at higher reaction temperatures than 150 degrees C, unlike those of poly(m-EOMB) and poly(p-EOMB), possibly due to inter- or intraester exchange side reactions. It was also found that the thermal properties and solubilities of these polymers were supposed with the proposed structures. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7835-7842, 2008