Four independent mol-ecules comprise the asymmetric unit of the title co-crystal, C(10)H(9)N(3)·C(7)H(5)NO(4), two for each component. Small conformational differences are noted for the benzoic acid derivatives, notably in the twists of the carb-oxy-lic acid residue out of the plane of the benzene ring to which it is connected [torsion angles = 167.62 (17) and 174.54 (17)°]. In the aniline derivative, the major difference is observed in the dihedral angles formed between the CN(3) and phenyl least-squares planes [1.51 (5) and 6.25 (6)°]. Pairs of mol-ecules associate via O-H⋯N and N-H⋯O hydrogen bonds leading to eight-membered {⋯HOCO⋯HNCN} hetero-synthons. The two-mol-ecule aggregates are consolidated in the crystal structure by C-H⋯O(nitro) and π-π inter-actions [shortest centroid-centroid distance between benzene rings = 3.6242 (10) Å].