Dimethyl 1-cyano-methyl-1H-pyrazole-3,5-dicarboxyl-ate.

The title mol-ecule, C(9)H(9)N(3)O(4), syhthesized from 1H-pyrazole-3,5-dicarboxylic acid and 2-bromo-acetonitrile, is approximately planar; the inter-planar angles between the pyrazole ring and the mean planes of the two carboxylate units and the cyanomethyl unit are 4.49 (10), 5.56 (9) and 5.03 (19)°, respectively. In the crystal, inversion dimers linked by pairs of weak C-H ⋯O bonds occur, and the packing is further stabilized by aromatic π-π stacking [centroid-centroid separation = 3.793 (4) Å].