Catalyst‐Free Visible‐Light‐Driven CH Alkylation, Arylation, and Acylation of Quinoxalin‐2(1 <i>H</i> )‐ones

Quinoxalin‐2(1 H )‐ones and their derivatives constitute a privileged class of bioactive scaffolds with broad pharmacological potential, including anticancer, antibacterial, and neuroregulatory activities. Developing efficient and sustainable strategies for their molecular diversification under mild conditions remains a long‐standing challenge in organic synthesis and medicinal chemistry. Here, we report a catalyst‐free, light‐driven CH functionalization strategy that exploits visible light and ambient air as the sole oxidant to achieve direct alkylation, arylation, and acylation of quinoxalin‐2(1 H )‐ones. This operationally simple protocol features excellent substrate scope and functional group tolerance, delivering a wide range of structurally diverse quinoxalin‐2(1 H )‐ones derivatives in a rapid and sustainable manner. Mechanistic investigations, supported by control experiments and spectroscopic studies, reveal that the transformation proceeds via the excitation of electron donor–acceptor complexes, which endows this system with the unique capability of enabling efficient CH functionalization without the need for any external catalyst.