The molecular structure of the iodide salt of the benzo-1,3,2-dithiazole cation, C6H4NS2+.I-, has been determined. The cation was found to be planar to within 0.04 Angstrom. The C2S2N ring is slightly asymmetrical, with S-N bonds of 1.584(5) and 1.617(6) Angstrom. There is also significant localization of bonds within the benzene moiety. The ions are found to stack approximately parallel to the x axis. Alternating stacks are related by a 2(1) screw axis.