The title compound, C 6 H 6 N 4 S, crystallizes with two independent molecules, A and B, in the asymmetric unit. Both independent molecules are almost planar [maximum deviations of 0.068 (6) Å in molecule A and 0.079 (6) Å in molecule B]. In the crystal, molecules A and B are linked by N-HÁ Á ÁS, N-HÁ Á ÁN and C-HÁ Á ÁS hydrogen bonds, forming a threedimensional network
