The article provides a comprehensive review of photoredox catalysis involving nickel–bipyridine (bpy) complexes, focusing on both photosensitized and direct excitation reaction processes. The review highlights the mechanisms of various bond transformation pathways and key findings, emphasizing how the ground- and excited-state geometric and electronic structures of Ni-based intermediates define the substrate scope of photoredox reactions. The authors identify knowledge gaps and suggest future research directions, including the development of synergistic approaches across physical, organic, and inorganic chemistry communities. They also discuss the importance of ligand field theory and the role of ligand noninnocence in determining the reactivity of Ni(II)–bpy complexes. The review covers detailed mechanisms such as reductive and oxidative single electron transfer (SET), photosensitization for homolysis, and triplet energy transfer (3EnT), providing insights into the complex interplay between light absorption, electron transfer, and bond formation in these reactions.The article provides a comprehensive review of photoredox catalysis involving nickel–bipyridine (bpy) complexes, focusing on both photosensitized and direct excitation reaction processes. The review highlights the mechanisms of various bond transformation pathways and key findings, emphasizing how the ground- and excited-state geometric and electronic structures of Ni-based intermediates define the substrate scope of photoredox reactions. The authors identify knowledge gaps and suggest future research directions, including the development of synergistic approaches across physical, organic, and inorganic chemistry communities. They also discuss the importance of ligand field theory and the role of ligand noninnocence in determining the reactivity of Ni(II)–bpy complexes. The review covers detailed mechanisms such as reductive and oxidative single electron transfer (SET), photosensitization for homolysis, and triplet energy transfer (3EnT), providing insights into the complex interplay between light absorption, electron transfer, and bond formation in these reactions.