In the title compound, C(19)H(19)BrN(2)O(2)S, the central thieno-pyrim-idine ring system is essentially planar, with a maximum displacement of 0.068 (3) Å. The attached cyclo-hexene ring adopts a half-chair conformation. The molecular conformation and crystal packing are stabilized by three intra-molecular C-H⋯O hydrogen bonds and two C-H⋯π inter-actions.