4-(aroyloxybenzoyloxy)benzonitriles with pronounced homeotropic SmA alignment

A series of 4-(aroyloxybenzoyloxy)benzonitriles was synthesised and their thermal, mesomorphic and photophysical properties were characterised. The lower homologues show only nematic phase, whereas higher members of the series exhibit long-range smectic A phase with a pronounced homeotropic organisation. This alignment is desired for in-plane charge conduction, allowing applications as active layer in organic field effect transistors. The compounds showed an intense absorption band between 250 to 300 nm.