The merger of transition metal catalysis and photocatalysis, termed metallaphotocatalysis, has recently emerged as a versatile platform for the development of new, highly enabling synthetic methodologies. Photoredox catalysis provides access to reactive radical species under mild conditions from abundant, native functional groups, and, when combined with transition metal catalysis, this feature allows direct coupling of non-traditional nucleophile partners. In addition, photocatalysis can aid fundamental organometallic steps through modulation of the oxidation state of transition metal complexes or through energy-transfer-mediated excitation of intermediate catalytic species. Metallaphotocatalysis provides access to distinct activation modes, which are complementary to those traditionally used in the field of transition metal catalysis, thereby enabling reaction development through entirely new mechanistic paradigms. This Review discusses key advances in the field of metallaphotocatalysis over the past decade and demonstrates how the unique mechanistic features permit challenging, or previously elusive, transformations to be accomplished.

过渡金属催化和光催化的合并（称为金属光催化）最近已成为开发新的，高度可行的合成方法的通用平台。光氧化还原催化可在温和条件下从丰富的天然官能团获得反应性自由基种类，并且与过渡金属催化结合使用时，该功能可实现非传统亲核试剂伴侣的直接偶联。另外，光催化可通过调节过渡金属配合物的氧化态或通过能量转移介导的中间催化物质的激发来辅助基本的有机金属步骤。金属光催化可提供独特的活化方式，这是过渡金属催化领域传统使用的补充方式，从而可以通过全新的机理范式进行反应开发。这篇综述讨论了过去十年在金属光催化领域的关键进展，并展示了独特的机械特征如何使挑战性的或以前难以捉摸的转化得以完成。