A satisfactory correlation between the polarographic reduction potentials and the calculated energies of the lower vacant molecular orbitals was found for a number of N-methylazinium cations. The result of the aza effect and the benzoannelation effect is a shift of the reduction potentials to the positive region by 0.2-0.5 and 0.2-0.7 V, respectively. Electron transfer from N,N,N′,N′-tetramethyl-p-phenylenediamine to the most electrophilic cations was recorded. The possibility of the occurrence of reactions involving aminoarylation of the acridinium cation via a one-electron mechanism was demonstrated electrochemically and by model reactions