The potassium metal reduction of p-benzoquinone (C6H4O2) in hexamethylphoshoramide (HMPA) followed by exposure to nitric oxide (NO.) gas results in radical-radical coupling between NO. and C6H4O2.-. Re-exposure of this solution to more potassium metal generates two new paramagnetic species which are observed via EPR; both are substituted p-benzosemiquinone systems with a nitrogen functional group. Repeating the experiment with 15NO. reveals that the nitrogen in these products does not come from the NO., but from a condensation reaction involving the HMPA solvent. The initial coupling of 15NO. (or NO.) and C6H4O2-. results in C-H bond activation forming nitroxyl (H15NO) and a reactive p-benzoquinone carbanion (C6H3O2-) intermediate which then attacks the HMPA. Proton decoupled 15N-NMR analysis reveals the presence of isotopically pure 15N nitrous oxide (15N15NO), which is a product formed from the dimerization of H15NO.