Symmetry Breaking in Achiral Porphyrins: Noncovalent Origins of Emergent Optical Activity

Chiral supramolecular assemblies of porphyrins have attracted significant interest due to their potential applications in asymmetric catalysis, chiroptical sensing, circularly polarized luminescence (CPL), and stimuli-responsive materials. Among the various strategies, the induction of optical activity in achiral porphyrins through noncovalent interactions with chiral molecules has emerged as a simple and effective approach for constructing well-defined supramolecular architectures. The dynamic nature of these assemblies provides insight into fundamental processes, such as chirality transfer, amplification, inversion, and memory effects. In this review, we summarize recent advances in chirality induction in achiral porphyrins and related chromophoric systems, with emphasis on the mechanisms governing the symmetry breaking in molecules and supramolecular assemblies. The discussed systems are categorized based on their modes of interaction leading to symmetry breaking, providing insights for the rational design of next-generation chiral functional materials.