This study reports the synthesis and characterization of a series of nitrile-functionalized tris(2-pyridylmethyl) amine (TPA) ligands—CNTPA, (CN)₂TPA, and (CN)₃TPA—and their corresponding iron (II) complexes. Systematic introduction of nitrile groups at the α-position induces a pronounced electron-withdrawing effect, increasing the ligand oxidation potential by ~110 mV per nitrile substituent, as demonstrated by electrochemical analysis. These complexes react with molecular oxygen to form stable μ-oxo diferric species, which can be reversibly reduced to regenerate the ferrous precursors. Structural studies reveal distinct coordination geometries: while the parent TPA yields a symmetrical dicationic μ-oxo complex with κ⁴-N coordination, CNTPA forms a neutral symmetrical dimer, and (CN)₂TPA produces a neutral, asymmetrically bridged species. A key finding is the correlation between ligand-induced electron deficiency at the iron center and oxygenation kinetics, with increased Lewis’s acidity accelerating O₂ activation. This supports a mechanism involving inner-sphere dioxygen coordination rather than outer-sphere electron transfer, which typically requires more negative reduction potentials. Furthermore, catalytic oxidation of cyclohexane to cyclohexanone under O₂, mediated by these complexes in the presence of zinc amalgam, demonstrates enhanced reactivity for (CN)₂TPAFeCl₂, aligning with its optimal balance of electronic activation and steric accessibility. These results highlight the critical role of ligand design in tuning metal centered reactivity for small-molecule activation and catalytic oxidation processes.