Chemical Approaches to Photoresponsive Fluorophores

Photoresponsive fluorophores, which enable precise spatiotemporal control of emission through light irradiation, are fundamentally important for advanced bioimaging and sensing applications. This review comprehensively surveys contemporary chemical strategies for the rational design of such smart optical probes. We systematically categorize and discuss the underlying design principles of major classes of photoresponsive fluorophores, including photoactivatable, photo‐deactivatable, photoconvertible, and dual‐activatable systems—the latter requiring the simultaneous occurrence of a specific biochemical event and external photonic input to trigger fluorescence. Detailed examination is provided on the key chemical approaches employed in their engineering, encompassing the use of caging groups, cage‐free molecular designs, directed photooxidation, electrocyclization reactions, and other phototriggered molecular rearrangements. By elucidating the intricate relationships between molecular structure and photophysical function, this overview underscores how innovative chemical design affords unprecedented spatiotemporal precision in fluorescence output, thereby expanding the toolbox for dynamic biological investigation and analytical detection.