Supramolecular Photosensitizers: From Engineering Principles to Functional Applications

Organic photosensitizers (PSs) are a class of photoactive molecules capable of generating reactive oxygen species (ROS) upon light irradiation, with their performance largely governed by their excited-state properties. While continuous efforts have focused on developing new PSs through molecular design, supramolecular chemistry provides a complementary and versatile platform for regulating the excited states of conventional PSs to construct novel supramolecular PSs. In this review, we summarize recent supramolecular engineering strategies that not only improve key properties, such as solubility, biocompatibility, ROS generation capability, and photostability, but also introduce advanced functionalities, including stimuli-responsive activation, assembly-induced emergence of photosensitizing activity, and regulation of Type I/Type II photodynamic pathways. Moreover, the applications of supramolecular PSs in diverse photochemical and biomedical fields are comprehensively overviewed, highlighting their unique advantages over small-molecule PSs. We hope that this review will bring more inspiration and possibilities for advancing the field of supramolecular PSs and inspire future innovations in supramolecular photochemistry and photomedicine.