To summarize, this book demonstrates the development of new and unprecedented methods in visible-light photocatalysis. The overall transformations unlocked new avenues in organic synthesis and provided a new vision for the future advancements and sustainable developments in this field. Undoubtedly, further discovery and development of new methods utilizing visible light will continue to grow in the next years, particularly due to the redox flexibility of photocatalysts to be employed with a range of reactions. However, a further detailed study of how factors such as temperature, solvent choice, catalyst choice, or additives, etc. could affect the reaction outcome. In addition, understanding the photo-physical parameters, such as redox potentials and the absorption or the emission properties of the catalysts and the reactants in the ground state and in the excited states are desired. Such studies will be necessary to understand how to better improve existing methods and develop new methods. More importantly, which may also provide answers to many of the existing anomalous results that have been observed in this fascinating area.