Abstract
In the title pymiridine-2,4-dione derivative, C14H16N2O2S, the dihedral angle between the six-membered rings is 66.69 (10)degrees. The molecule is twisted about the Cp-S (p = pyrimidine) bond, with a C-S-C-N torsion angle of-19.57 (16)degrees. In the crystal, adjacent molecules form inversion dimers through pairs of strong N-H center dot center dot center dot O hydrogen bonds, generating an R-2(2) (8) ring motif. The dimers are connected into chains extending along the c-axis direction through additional NH center dot center dot center dot O hydrogen bonds.