Copolymers of a liquid crystalline monomer, 215-bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS), with St and MMA were prepared by free radical polymerization at low conversion in chlorobenzene with 2,2 '-azobisisobutyronitrile (AIBN) as initiator. The copolymers of poly(MPCS-co-St) and poly(MPCS-co-MMA) were characterized by H-1 NMR and GPC. The monomer reactivity ratios were determined by using the extended Kelen-Tudos (EKT) method. Structural parameters of the copolymers were obtained from the possibility statistics and monomer reactivity ratios. The influence of MPCS content in copolymers on the glass transition temperatures of copolymers was investigated by DSC. The thermal stabilities of the two copolymer systems increased with an increase of the molar fraction of MPCS in the copolymers. The liquid crystalline behavior of the copolymers was also investigated using DSC and POM. The results revealed that the copolymers with high MPCS molar contents exhibited liquid crystalline behaviors. (c) 2005 Wiley Periodicals, Inc.