Molecules of the title compound (BPDH2, C14H14N4-S2) belong to the Ci point group, with only half of the molecule in an asymmetric unit. The molecule is planar to within 0.006 A, with intramolecular N-H...S and N-H...N hydrogen bonds [H...N 2.10 (4) and H...S 2.48 (4) A].