Beyond Aggregation: Engineering AIEgens from Molecular Design to Supramolecular Assembly for Advanced Photophysical Function

Since the introduction of the concept of aggregation‐induced emission (AIE) in 2001, AIE molecules have garnered significant attention as versatile building blocks with much application potential. To optimally exploit their features, much effort has been devoted to exploring the fundamental photophysical mechanisms underlying AIE luminogens (AIEgens). Typically, AIEgens must transition from the monomeric to the aggregated state to exhibit their characteristic emission, a feature critical for practical applications. As a result, precise control over the photophysical properties of AIEgens in their aggregated state has become a key focus of AIE research. Drawing on both molecular and supramolecular theories, researchers have proposed and elucidated a range of models to better understand the relationship between aggregation and photophysical properties. Building on these insights, the rational design of AIEgenic nanostructures with tunable photophysical properties holds significant promise for enhancing their performance in biomedical applications, including fluorescence imaging, photoacoustic imaging, photodynamic therapy, and photothermal therapy. This review aims to provide a comprehensive overview of strategies for the rational design of AIEgens, modulation of their aggregation behavior, and development of assembly approaches to tailor the photophysical properties of the resulting nanostructures, guiding the construction of therapeutic agents for biomedical use.