The title mol-ecule, C(12)H(11)N(3)O(4), is essentially planar, the r.m.s. deviation for all non-H atoms being 0.068 Å. An intra-molecular C-H⋯N hydrogen bond occurs. The crystal packing is dominated by π-π inter-actions [shortest centroid-centroid distance = 3.6312 (16) Å], which lead to supra-molecular chains that are linked into a three-dimensional network via C-H⋯O contacts. The crystal was found to be a non-merohedral twin (twin law -1 0 0/0 -1 0/ 0.784 0 1), the fractional contribution of the minor component being approx-imately 22%.