The imidazopyridine ring system in the title compound, C(9)H(8)BrN(3)S, is almost planar [r.m.s. deviation of the C and N atoms = 0.007 (1) Å]. The S and methyl-ene C atoms connected to the five-membered ring lie within this plane. The remaining two methyl-ene groups of the thia-zine ring are disordered over two sets of sites in a 0.817 (5):0.183 (5) ratio.