Three‐Stage Aromaticity Switching in Boron(III) and Phosphorus(V) N‐Fused p ‐Benziporphyrin

Insertion of PCl 3 or PhBCl 2 into 5,10,15,20‐tetraaryl‐ p ‐benziporphyrin prompted an intramolecular fusion affording anti‐aromatic phosphorus(V) and non‐aromatic boron(III) complexes of two N‐fused dihydro‐ p ‐benziporphyrin isomers. These macrocycles are classified as carbatriphyrin due to the common [CNN] coordination. A sequence of direct transformations, triggered by protonation or two‐electron redox processes, afforded a set of three mutually convertible N‐fused p ‐benziporphyrinoids, with distinct anti‐aromatic, non‐aromatic, and aromatic spectroscopic features.