Triply‐Linked N‐Confused Porphyrin Dimers: Cross Conjugation‐Mediated Expansion of π‐Conjugation

meso-meso', α-α', β-β'-Triply-linked N-confused porphyrin (NCP) dimers were synthesized via stepwise oxidative coupling reactions of 5,10,15-triaryl-NCP, followed by nickel or silver metalation. The novel dimers possess extended π-conjugation throughout the entire fused dimer structures, leading to Hückel 36π-antiaromaticity and 38π-aromaticity for the nickel and silver complexes, respectively. Theoretical investigations using the gauge-including magnetically induced current (GIMIC) method reveal the pivotal role of NCP cross-conjugation and NH tautomerism in forming the global π-conjugation circuit. Redox reactions induce a unique switching of the π-conjugation circuits, transforming delocalized π-conjugation into localized π-conjugation in the NCP macrocycle, giving rise to an antiaromatic domain at the bay area.