A new method for investigating the mechanisms of nitric oxide release from NO donors under oxidative and reductive conditions is presented. Based on the fragmentation of N-nitrosoamines, it allows generation and spectroscopic characterization of nitrenium cations, amide anions, and aminyl radicals. X-irradiation of N-nitroso-N,N-diphenylamine 1 in Ar matrices at 10 K is found to yield the corresponding radical ions, which apparently undergo spontaneous loss of NO center dot under the conditions of this experiment (1(center dot+) seems to survive partially intact, but not 1(center dot-)). One-electron reduction or oxidation of 1 is observed upon doping of the Ar matrix with DABCO, an efficient hole scavenger, or CH2Cl2, an electron scavenger, respectively. The resulting diphenylnitrenium cation, 2(+), and the diphenylamide anion, 2(-), were characterized by their full UV-vis and mid-IR spectra. The best spectra of 2(+) and 2(-) were obtained if 1 was homolytically photodissociated to diphenylaminyl radical 2(center dot) and NO center dot prior to ionization. 2(+) and 2(-) are bleached on irradiation at < 340 nm to form 2(center dot) or, in part, 1. DFT and CCSD quantum chemical calculations predict that the dissociation of 1(center dot+) and 1(center dot-) is slightly endothermic, a tendency which is partially reversed if one allows for complexation of the resulting 2(+) (and, presumably, 2(-)) with NO center dot. The method described in this work should prove generally applicable to the generation and study of nitrenium cations and amide anions R2N+/- under matrix and ambient conditions (i.e., in solution).