The molecule of the title compound, C11H8BrN3O, is close to planar (r.m.s. deviation of all 16 non-H atoms = 0.103 Å), a conformation stabilized by an intramolecular N—H⋯N hydrogen bond, which generates an S(5) ring. In the crystal structure, supramolecular chains mediated by C—H⋯O contacts (along a) are linked into a double layer via N⋯Br halogen bonds [3.207 (5) Å] and C—Br⋯π interactions [Br⋯ring centroid(pyrazine) = 3.446 (3) Å]. The layers stack along the b axis via weak π–π interactions [ring centroid(pyrazine)⋯ring centroid(benzene) distance = 3.803 (4) Å].