In the title compound, C21H11N5S, the pheno-thia-zine unit has a butterfly structure, and the central six-membered ring adopts a boat conformation. The dihedral angle between the benzene rings is 127.64 (6)°, which is smaller than those reported for similar compounds because of the steric repulsion between the pheno-thia-zine and its tetra-cyano-1,3-butadiene substituent. The di-cyano-vinyl groups are almost orthogonal to one another, making a dihedral angle of 80.58 (6)°. In the crystal, the mol-ecules are aligned along the b axis. Four kinds of weak C-H⋯N inter-actions are recognized, one of which connects the mol-ecules into a one-dimensional array and the remaining three link these arrays.