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.