Voltammetric and spectroelectrochemical-ESR studies of the electro-reduction of Perezone and five substituted anilinoperezones (R = -H, -OCH3; -CH3; -CN, -Br) and their dihydroderivatives in acetonitrile were made. The results showed that in PZ and APZs the double bond at C(12)-C(13) can be involved with the quinone ring. The values of EpcI-EpaI of APZHs indicated a increase in the acidity of the -OH, caused by the lack of the double bond and the logical production of the hydroquinone. On the other hand, the values corresponding to APZs imply that their electro-reduction process would stop at the hydroquinone monoanion, what is in agreement with ESR data. This suggests that, in the radical dianion structure, the spin density at quinone ring changes by the presence or absence of the olefinic bond. However, the magnitude of these changes is very small, which suggests that the interaction present involves a small energy change between both structures