LED Light‐Induced Modulation of the Anticancer Activity of a [(2‐(6‐Bromopyridin‐2‐yl)‐1 H ‐benzo[d]imidazol‐6‐yl)(phenyl)methanone]‐Based Iridium(III) Complex

ABSTRACT Metal complexes are emerging as powerful agents in light‐activated cancer therapy, a cutting‐edge therapeutic strategy for combating cancer and other serious diseases. Among them, iridium (Ir)‐based photosensitizers have recently gained significant attention, driving innovation in photo‐activated cancer therapy and opening new avenues for targeted treatment. Building on this momentum, we have designed a novel benzimidazole‐based iridium complex, [LIr] , which demonstrates remarkable potential as a phototherapeutic agent. Upon activation with a direct light source from a 40 W white LED (400−700 nm), with a fixed distance of 15 cm between the light source and the samples maintained throughout all the experiments, [LIr] exhibits potent catalytic activity, efficiently oxidizing key cellular antioxidants: converting glutathione (GSH) to glutathione disulfide (GSSG), NADH to NAD + , and NADPH to NADP + . This redox disruption compromises cancer cell defenses and enhances therapeutic efficacy. In addition, light activation of complex [LIr] generates a burst of reactive oxygen species (ROS), including the highly cytotoxic singlet oxygen, with a notable singlet oxygen quantum yield. This multifaceted reactivity not only disrupts cellular redox balance but also induces oxidative stress in targeted cancer cells.