The title compound, C6H4ClN3, is essentially planar with the pyrrole and pyrimidine rings inclined to one another by 0.79 (15)degrees. In the crystal, molecules are connected via pairs of N-H center dot center dot center dot N hydrogen bonds, forming inversion dimers. These dimers are linked via C-H center dot center dot center dot N interactions, forming a two-dimensional network parallel to (10 (1) over bar).