Visible‐Light‐Driven Heteroaryl Azo Switches with High‐Efficiency Photoisomerization for Advanced Photochromic Systems

ABSTRACT Azobenzenes are among the most widely used molecular photoswitches owing to their rapid response, excellent fatigue resistance, facile synthesis, and scalability. However, their isomerization typically requires ultraviolet (UV) light, which has limited penetration and may cause material degradation. Achieving high bidirectional photoconversion, visible‐light responsiveness, and suitable Z ‐isomer thermal half‐lives remains both crucial and challenging. Here, we report a series of pyrazole‐based azo photoswitches responsive to visible‐light. These molecules exhibit efficient cis ‐to‐ trans photoisomerization (>90% upon 405 nm irradiation) and nearly quantitative trans ‐to‐ cis conversion (>98% upon 532 nm irradiation). Light‐responsive systems constructed from these azo photoswitches display a well‐balanced performance profile. Owing to their practicality and robust switching behavior, these azopyrazole photoswitches hold strong potential for diverse light‐responsive applications.