Over the last two decades, photoredox catalysis has become a widespread and useful tool in organic synthesis. This is in part due to the use of much milder reaction conditions in photocatalysis in comparison to the typically higher temperatures and stoichiometric use of reductants, some of which are toxic, often required in traditional thermal synthesis. Additionally, photocatalysis provides alternative and new chemoselectivity, allowing a route to synthons not easily accessible using other synthetic methodologies. As such, photocatalysis has received a resurgence of interest, with just under 17,000 papers published on this topic between 2020 and 2021 combined. Typically, transition metal complexes based on ruthenium(II) or iridium(III) metals have been the most popular photocatalysts used in homogeneous photocatalysis on account of their well understood and desirable photophysical properties, including their visible-light absorption, long-lived excited states, and versatile redox potentials that can be easily tuned through variation of the ligand field around the metal. However, issues relating to toxicity, natural abundance of these metals and associated cost have motivated the search for alternative photocatalysts, with both Earth-abundant metal complexes 7 and organic compounds 3 identified as potentially viable options for their replacement.