One non chiral homopolyester and five chiral copolyesters were prepared by polycondensations of 2,5-bis(dodecyloxy)terephthaloylchloride and 4,4＇-dihydroxybiphenyl or mixtures of this diphenol and isosorbide. The resulting polyesters were characterized by viscosity measurements, elemental analyses, H-1 n.m.r. measurements, optical microscopy, DSC-measurements and X-ray measurements with synchrotron radiation at variable temperatures. If more than 20% of the 4,4＇-dihydroxybiphenyl were replaced by isosorbide the copolyesters lost their thermotropic character. All polyesters with 20% or less isosorbide proved to be semicrystalline thermotropic materials showing three phase transitions : firstly a melting process (T-m1), secondly a transition from a sanidic LC-phase to a normal nematic or cholesteric melt (T-m2) and finally to the isotropisation (Ti). The copolyester containing 10% isosorbide was capable of forming a Grandjean texture.