Discrete Conjugated Porphyrin Tapes with an Exceptionally Small Bandgap

An Ag^I‐promoted meso–meso coupling reaction has been extended to prepare discrete 100 nm long linear arrays of porphyrins. Oxidation of the resulting phenyl end‐capped meso–meso linked porphyrins using a combination of 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) and Sc^III(OTf)₃ directly produces fully π‐conjugated fused porphyrin arrays (porphyrin tapes) of 10 nm molecular size. This research news article presents their synthesis, X‐ray crystal structures, and optical and electronic properties. Among these, the extremely small highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) optical gaps that reach into the infrared region suggest many applications of these compounds in materials science.