Photo-responsive and electrically switchable mesophases in a novel class of achiral bent-core azo compounds

The first examples of electrically switchable and photo-responsive mesophases in a novel class of bent-core azo compounds, consisting of only five aromatic rings and no imino functionality (-CH=N-), are reported. The mesophases have been identified as B₁, B₂ and a new mesophase, B_x, on the basis of the results of polarizing optical microscopy, differential scanning calorimetry, X-ray diffraction, and electro-optical response. Preliminary but profound photo-induced effects on the transition temperature from isotropic to the B₂ mesophase of one of the azo compounds are also presented.