π-Expanded borazine: An ambipolar conjugated B-π-N macrocycle

Staying at a B 'N' B: A highly symmetric cyclic structure in which N donor and B acceptor sites are alternating (see picture) is found for the first ambipolar π-conjugated B-N macrocycle. The donor-π-acceptor arrangement results in mutual interactions between B and N and a pronounced solvatochromic effect on the emission. The strong luminescence in solution also lends itself to use in anion recognition.