The kinetics of oxidation of N,N-dimethyl-N’-(1H-benzimidazol-2-yl) formamidine (BIF) and N,N-dimethyl-N’-(benzthiazol-2-yl) formamidine (BTF) by permanganate ion in diluted sulfuric acid medium has been investigated spectrophotometrically at a constant ionic strength of 0.2 mol dm-3 and at a temperature of 25°C. The reactions of both organic reductants with permanganate ion showed a first order dependence with respect to [MnO4 − ] and fractional-first order dependences with respect to both hydrogen ion and reductants concentrations. Increasing either ionic strength or dielectric constant of the reactions media had no significant effect on the oxidation rates. Manganese(II) ion was found to auto-catalyze the oxidation reactions with less than unit order dependences. The final oxidation products of BIF and BTF were identified by both spectroscopic and chemical tools as 2-aminobenzimidazole and 2-aminobenzthiazole, respectively, in addition to dimethylamine and carbon dioxide. Under comparable experimental conditions, the oxidation rate of BIF was higher than that of BTF. A plausible reactions mechanism has been suggested and the reaction constants involved in the mechanism have been evaluated. The activation parameters with respect to the second order rate constants have been computed and discussed