Review on recent trends and prospects in π‐conjugated luminescent aggregates for biomedical applications

Abstract Metal‐free organic molecules with structurally diverse aggregation‐induced emission (AIE) behavior and new functional photophysical properties reveal unique structure–property relationships, especially bright luminescence, and have attracted extensive attention in the past few decades. Despite tremendous progress on fluorescent molecules development, the extended π‐conjugated organic AIE probes with their nanorange self‐assembly, coassembly, unique morphology, high biocompatibility, and light‐harvesting capabilities enable them as potential candidates in numerous translational application perspectives. In particular, a few important classes of AIE light up small molecules, supramolecules, oligomers, polymers, including nanoparticles and photosensitizer molecules, with their emerging properties of thermally activated delayed fluorescence, room temperature phosphorescence, including emission switching stimuli‐responsive behavior and multifunctional properties, have been boosted by the rare features of aggregation at their condensed or solid states. This review highlights salient features of AIE‐based emitters, encompassing molecular design strategies, stimulating photophysical properties, mechanistic aspects, and their efficacy in various electronic and biomedical applications, broadly covering properties of small molecules to oligomers, macromolecules to polymers.