The SNS+ cation (in SNSAsF6) underwent symmetry-allowed concerted cycloadditions with the aryl nitriles RCN (R = 2,5-Me2C6H3, Ph, p-O2NC6H4, and 3,5-(O2N)2C6H3) and diphenylacetylene. The cycloadducts [Formula: see text] (R = 2,5-Me2C6H3, Ph, p-O2NC6H4, and 3,5-(O2N)2C6H3) and Ph [Formula: see text] were characterized by elemental analyses and IR and NMR (1H, 13C, 14N) spectroscopies. The reduction of [Formula: see text] gave the corresponding 1,3,2,4-dithiadiazoles [Formula: see text], which in turn rearranged to the corresponding 1,2,3,5-dithiadiazoles [Formula: see text]. The rate of this rearrangement was correlated with the ionization potentials of the corresponding nitriles. The radicals [Formula: see text] (R = Ph, p-O2NC6H4) were isolated as pure compounds, and characterized by mass spectrometry, IR, FT-Raman, and ESR spectroscopies. The reduction of [Formula: see text] led to neutral radical [Formula: see text], which is stable in solution up to ca. 0.5 M, but decomposes at higher concentrations.