Electrochemical studies were carried out on a series of cyclic 1,2-diones under nonaqueous conditions. From thereduction potentials and Hucke! molecular orbital calculations, the increase in antiaromatic destabilization of cyclobutenedione upon reduction is estimated to be at least 14 kcal/mol. The EPR spectrum of the radical anion of naphtho[b ]cyclobutadienoquinone is presented. Also, INDO calculations were carried out on several of the diones and the results are consistent with the experimental observations.