Metalloenzymes such as Cytochrome P450s and Galactose Oxidases utilize non-innocent ligands to generate reactive, high-valent intermediates that are crucial for oxidation reactions.1 This approach is particularly effective with late 3d metals, where accessing high-valent states is notably difficult.2 In this context, NiII(salen) complexes have emerged as promising candidates for generating high-valent nickel species.3,4 This presentation explores one such investigation, where NiII(salen) was treated with mCPBA, yielding a novel Ni(III) bisphenoxyl diradical species, formally analogous to a high-valent Ni(V) species. Electrochemical and spectroscopic studies, including UV-Vis and EPR, revealed oxidation events at both the ligand and the metal center, producing the Ni(III) bisphenoxyl diradical species, NiIII(L••).5 However, using mCPBA limits understanding of the processes involved in generating a formal Ni(V) species. By varying the potential, ceric ammonium nitrate concentration with acid, and temperature, we observed the formation of intermediate species, including Ni(III) and a formal Ni(IV) species, before the emergence of a formal Ni(V) species. A slight modification of the salen ligand led to the formation of a novel Lewis acid-bound formal Ni(V) species, which exhibited an exceptionally high molar absorptivity value (50,000 M-1 cm-1 ) under varying conditions. Such a high molar absorptivity in the visible region is unprecedented for any non-heme system. However, the use of salen as a ligand has historically limited the characterization of formal Ni(IV) species, as both the nickel center and ligand share the unpaired spin. To address this, pseudopeptide-based Ni complexes were employed, enabling the formation and stabilization of high-valent formal Ni(IV) species from a Ni(III) precursor. The intermediates described here have also been explored as potential candidates for key oxidation reactions. Our research offers new perspectives on high-valent nickel species and paves the way for the development of more efficient catalytic systems with broader applications in synthetic chemistry.