Recent advancements in the molecular design of deep-red to near-infrared light-absorbing photocatalysts

Photocatalysis has traditionally relied on photocatalysts that primarily absorb short-wavelength ultraviolet-visible (UV-vis) light. However, recent advancements have led to the development of photocatalysts that can absorb deep-red to near-infrared light. These near-infrared photocatalysts (NIR-PCs) offer distinct advantages over traditional UV-vis photocatalysts, including deeper tissue penetration and reduced interference from competing absorption processes. Herein, we summarize the latest advancements in their molecular design based on three activation mechanisms: one-photon absorption, triplet-triplet annihilation upconversion, and two-photon absorption. This review aims to present not only various organic transformations facilitated by NIR-PCs but also the diverse molecular engineering strategies that have been employed in the design and development of NIR-PCs, particularly focusing on those with exceptional absorption capabilities in the NIR region. Finally, a brief overview of the current challenges and opportunities for future explorations of NIR photocatalysis is presented, underscoring the growing significance of NIR-PCs in advancing the frontiers of photocatalysis.