The mechanistic insights into the reactivities of H2Q toward electrogenerated O2 •-in DMF were investigated using electrochemistry and digital simulation analyses. The simple one-kinetic 2PCET without forming any intermediates was feasible for two PTs and one ET in the simulations. However, the 2PCET between H2Q and O2 •-via three elementary steps, formation of PRC, 2PCET, and dissociation of PC, were adopted to fit the features of the experimental curves and clarify the detailed mechanism. Our attempts to simulate the experimental observations sufficiently reproduce the gross features of the voltammograms to assign the characteristic waves. The results obtained in this paper provide complicated but reasonable explanations of the features of the voltammetric behavior exhibiting the 2PCET.