Sulfonyl azide isocyanate, (OCN)S(O)(2)N-3, was prepared and characterized by IR (gas, matrix-isolation), Raman (liquid), and UV-vis spectroscopy. Upon flash vacuum pyrolysis (FVP) at ca. 1000 K, gaseous (OCN)S(O)(2)N-3 decomposes completely and yields fragments N-2, SO2, SO3, NCN, N-3, NCO, CO, CN, and NO. In contrast, the azide splits off N-2 and furnishes a transient triplet sulfonyl nitrene intermediate (OCN)S(O)(2)N upon a 266 nm laser irradiation in solid Ne-matrix at 2.8 K. Subsequent photolysis of the nitrene with visible light (lambda = 380-450 nm) results in oxygen-shifted Curtius rearrangement to a novel nitroso sulfoxide (OCN)S(O)NO. For comparison, the photodecomposition of the closely related sulfonyl diazide O2S(N-3)(2) in a solid Ar matrix was also studied. Upon an ArF excimer laser (193 nm) photolysis, O2S(N-3)(2) decomposes and yields N-2, SO2, and OSNNO via the intermediacy of an elusive sufonyl nitrene N3S(O)(2)N. Further visible light irradiation (lambda > 395 nm) leads to depletion of N3S(O)(2)N and OSNNO and concomitant formation of SO2 and N-2. The identification of the intermediates in cryogenic matrixes by IR spectroscopy was supported by N-15-labeling experiments and quantum chemical calculations. The mechanism for the decomposition of both sulfonyl azides (OCN)S(O)(2)N-3 and O2S(N-3)(2) was discussed on the basis of the observed intermediates and the calculated potential energy profiles.