Liquid crystalline benzothiophene derivatives

The role and position of the benzothiophene core in several series of calamitic liquid crystals was examined. Benzothiophene and its lateral 3‐chloro‐ and 6‐methoxy‐substituted derivatives, where the benzothiophene unit is in the terminal position, support formation of broad nematic phases. On the other hand, introduction of a longer alkoxy chain in the 6‐position or positioning the benzothiophene in the centre of the molecular structure led to appearance of smectic C and/or smectic A phases.