Trivalent boron as acceptor chromophore in asymmetrically substituted 4,4′-biphenyl and azobenzene for non-linear optics

[4′-(Dimethylamino)biphenyl-4-yl]dimesitylborane (BNB) and [4′-(dimethylamino)phenylazophenyl-4-yl]dimesitylborane (BNA) have been prepared and studied by a solvatochromic technique. The high second-order hyperpolarisability coefficients βCT determined by this technique, 37 and 240 × 10–30 esu, respectively, show that this new family of materials is of interest for non-linear optics.