Abstract
It was found that mesogenic triphenylenes with six long-chain azobenzene units exhibit different mesomorphisms depending on the linkage groups between triphenylene and azobenzen units. Furthermore, some homologues show layered smectic and stacking columnar phases of which orientational orders of molecules are formed by the rod-like (calamitic) and disc-like(discotic) shapes of molecules, respectively. It was also found that the C14 homologue is a first mesogen which exhibits multiple phase transitions among Col, Sm and Iso phases depending on the photo intensity to cause trans-cis isomeirzation of the azobenzene units.
