Copolycondensations of (S,S)-2,5-bis(2-methylbutyloxy)terephthaloylchloride with 2,5-bis(dodecyloxy)terephthaloylchloride and with 4,4’-bistrimethylsiloxybiphenyl yielded a series of novel chiral thermotropic copolyesters. These polyesters were characterized by elemental analyses, inherent viscosities, H-1-NMR spectroscopy, optical rotations, optical microscopy, DSC measurements, and WAXS powder patterns recorded with synchrotron radiation under variation of the temperature. All homo- and copolyesters formed a solid sanidic layer structure with melting temperatures (T-m) greater than or equal to 200 degrees C. A broad enantiotropic nematic or cholesteric phase is formed above T-m with isotropization temperatures (T(i)s) in the range of 275-325 degrees C. Yet, the T-m of the chiral homopolyester is so high (378 degrees C) that the melting process is immediately followed by rapid degradation. The cholesteric phases of the copolyesters displayed unusual mobile schlieren textures, but a stable Grandjean texture was never obtained. Cholesteric domains consisting of loose bundles of more or less helical main chains are discussed as supramolecular order responsible for the observed textures and their pronounced temperature dependence.