The use of 1,4-phenylene-containing tripyrrane analogs provides a general route to expanded p-benziporphyrins. The course of macrocyclization shows a striking dependence on the steric bulk of meso substituents.
A facile synthesis of electronically rich phenylene-bridged bis-pyrrolo[1,2-a]indole crowned macrocycles 1–3 is reported via intramolecular fusion under oxidation conditions and formation of corresponding cation radicals in the presence of TFA with huge bathochromic shift (∼500 nm), leading to NIR (850–1400 nm) absorption.