The title compound, C(14)H(10)BrN(3)O(3)S, crystallizes as two concomitant polymorphs that differ in colour (one yellow and one colourless). Only the structure of the colourless form could be determined. The mol-ecule exists in the thio-amide form with an intra-molecular N-H⋯O=C hydrogen bond across the thio-urea system. Mol-ecules are linked into layers parallel to (120) by Br⋯O(nitro) contacts [3.103 (1) Å], classical hydrogen bonds from the other NH function to the S atom and N(nitro)⋯O=C contacts. The layers are linked by weak C-H⋯O(nitro) hydrogen bonds to produce the observed three-dimensional network.