In the title mol-ecule, C15H9N3O2S, the central imidazo[2,1-b][1,3]benzo-thia-zole heterotricyclic unit is essentially planar (r.m.s. deviation = 0.021 Å). The terminal phenyl ring and nitro group are twisted by 9.06 (1) and 11.02 (4)°, respectively, from the mean plane of the heterotricycle. In the crystal, mol-ecules are linked by π-π stacking inter-actions into columns along [100]; the inter-planar distance between neighboring imidazo[2,1-b][1,3]benzo-thia-zole planes within the columns is 3.370 (2) Å. Furthermore, the columns interact with each other by secondary S⋯O [2.9922 (10) and 3.1988 (11) Å] inter-actions, forming a three-dimensional framework.