Abstract: Photoclick chemistry, as an interdisciplinary field bridging click chemistry and photochemistry, combines the spatiotemporal resolution of light-controlled reactions with the high efficiency and selectivity of traditional click reactions, offering a robust approach for precise molecular construction. In recent years, the photoclick reaction system based on 9,10-phenanthrenequinone and electron-rich alkene (PQ-ERA) has emerged as a prominent research focus due to its unique kinetic characteristics, visible-light driving capability, and high bioorthogonality. This review systematically summarizes the latest research advances in PQ-ERA, beginning with an analysis of its reaction mechanism. It further comprehensively outlines its innovative applications in bioimaging, such as bioorthogonal labeling and the precise construction of positron emission tomography (PET) tracers and in the development of dynamic smart materials, including photopatterning, photoresponsive functional hydrogels, and adhesive materials. Finally, it delves into key system optimization directions for PQ-ERA, such as enhancing reaction activity and achieving bathochromic shifts in the driving wavelength.