Here, we report a mechanism by which AC electrolysis controls the one-or two-electron oxidation of amines to amino radicals or iminium cations, enabling selective αamine functionalization by simply adjusting the AC frequency. In this mechanism, the degree of amine oxidation is controlled by managing the redox environment where the amino radical cation III is deprotonated to amino radical IV, utilizing the alternating redox environment of AC electrolysis. When deprotonation of III occurs in an oxidizing environment, IV is further oxidized to iminium cation II for nucleophilic addition; otherwise, IV remains available for radical-based reactions (Figure ). Such delicate reaction control requires precise synchronization of the dynamic redox environment and the deprotonation reaction kinetics at the "correct" AC frequency. However, because the deprotonation kinetics of substrates varies significantly, each substrate requires individual reaction optimization, making the empirical trial-and-error reaction optimization approach impractically time-consuming (several days per substrate). Therefore, we developed a convenient electroanalytical method to identify the optimal AC frequency in a few minutes to address it.