In the title compound, C8H8N6, two imidazolyl groups are separated by a zigzag –CH=N—N=CH– linkage. An inversion center is located at the mid-point of the N—N single bond and the complete molecule is generated by symmetry. In the crystal, each molecule forms four N—H...N hydrogen bonds with two neighbouring molecules to constitute a one-dimensional ladder-like structure propagating along the a-axis direction.