The polarographic reduction potentials of a series of aromatic sulfones and homologous alkyl tosylates in anhydrous NN-dimethylformamide have been measured. The relation between reduction potential and structure is discussed on the basis of HMO. calculations, under the assumption that compounds PhSO₂X (X = NR¹R², OR, halogens) are sulfone derivatives A critical approach is made of the use of the Taft-Hammett relation for correlating half-wave potentials. The different reduction mechanisms at the electrode observed in aprotic and protic media for the above compounds are satisfactorily accounted for by simple MO. calculations.