A series of liquid crystalline aromatic polyesters containing 3,3’-dimethylbiphenyl-4,4’-dicarboxylic acid and 3,4’-dimethyl-biphenyl-4,3’-dicarboxylic acid was prepared by a melt polycondensation procedure and characterized by elemental analysis, DSC and TMA measurements, and optical polarizing microscopy. An optimal composition of the copolymer having a melting temperature around 300 degrees C is proposed and the rheological behavior is discussed. Most of the mechanical properties of this copolymer were found to be close to those of Vectra A950(R) used as a reference sample.