The photogeneration of stable radicals is important but still challenging in the field of optical switching, displays, and other devices. Herein, crystalline 9-anthracene carboxylic acid (9-AC) and a mononuclear complex constructed from this ligand were for the first time discovered to show radical-induced photochromism and photomagnetism after Xe lamp light irradiation. This study finds a simple radical-actuated photochromic molecule for constructing a novel system of photochromic materials.