A series of fully aromatic, thermotropic polyesters, derived from 3,4’-dihydroxybenzophenone and various aromatic dicarboxylic acids, was prepared by the high-temperature solution polycondensation method and examined for thermotropic behavior by a variety of experimental techniques. The aromatic dicarboxylic acids used in this study were 2,6-naphthalenedicarboxylic acid, 4,4’-bibenzoic acid, and terephthalic acid. The two homopolymers of 3,4’-DHB with either 2,6-NDA or 4,4’-BBA formed nematic LC phases at 285 degrees C and 255 degrees C and also exhibited isotropization transitions (T-i) at 317 degrees C and 339 degrees C, respectively. The copolymer of 3,4’-DHB with 50% TA and 50% 2,6-NDA also formed a nematic LC phase and had a broader range of LC phase than that of its respective homopolymers. Two other copolymers of 3,4’-DHB, both containing 50% 4,4’-BBA, also formed nematic LC phases at low T-f values. All of the thermotropic polyesters had high thermal stabilities.