The majority of photoreactions reported in the literature rely on wavelengths within the UV and-to a lesser extent-visible regime for activation, either by directly triggering the reaction or by photocatalysis. However, photoreactions induced by near-infrared (NIR) light are highly attractive for biomedical applications as NIR light can penetrate deeper into tissue and causes less damage to photosensitive biological systems. Recently, upconverting nanoparticles (UCNPs) have been employed by us and others to assist NIR photoinduced reactions. UCNPs convert NIR light to UV or visible light, which can trigger photoreactions of conventional UV or visible-light-sensitive compounds. In the current Concept article, we introduce the fundamentals of UCNP-assisted photochemistry and highlight selected future applications and innovative potential for the field.