The structure of the title compound, C(12)H(9)N(5)O(4), reveals an almost planar molecule (r.m.s. deviation = 0.061 A), in which the interplanar angle between the phenyl rings is 5.7 (1) degrees and the largest interplanar angle is that between the phenyl ring and the nitro group of one of the 4-nitrophenyl substituents [8.8 (3) degrees ]. The observed molecular conformation suggests a delocalization of pi-electrons extended over the diazoamine group and the terminal aryl substituents. Intermolecular N-H.O interactions between the twofold screw-related molecules give rise to helical chains along the [010] direction. Intermolecular C-H.O interactions then generate sheets of molecules in the (10-1) plane, and these sheets are held together by N.C and O.O pi-pi interactions.