The prominent features in the molecular structure of the title compound (alternative name: 2-diethylcarbamoyl-1,1,3,3-tetraoxo-1,3,2-benzodithiazole), C(11)H(14)N(2)O(5)S(2), arise in the urea moiety S(2)N-C(O)-N'C(2): the sum of the angles at N is 332.3 (1) degrees, the N-C(O)-N'C(2) unit is planar, and distances N-C(O) = 1.494 (3) A, N'-C(O) = 1.325 (2) A and C-O = 1.215 (2) A. The molecules are associated via five C-H...O hydrogen bonds to form layers parallel to the yz plane. This compound and its dimethyl homologue, which were synthesized by treating the silver salt of o-benzenedisulfonimide with carbamoyl chlorides, are prone to rapid hydrolysis at the weak N-C(O) bond. For both molecules, the rotational barrier about the partial N'-C(O) double bond is ca 50 kJ mol(-1) at 250 K (from dynamic (1)H NMR experiments).