4-tert-Butyl-amino-3-nitro-benzoic acid.

In the title compound, C(11)H(14)N(2)O(4), all non-H atoms lie in a mirror plane except for one of the methyl groups which deviates from the mirror plane by 0.919 (3) Å and is twisted by a torsion angle of 62.9 (2)°. An intra-molecular N-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal packing, the mol-ecules are linked together by O-H⋯O hydrogen bonds, forming dimers with graph-set motif R(2) (2)(8) which propagate along the a-axis direction. C-H⋯O contacts link adjacent dimers with a graph-set motif C(2) (2)(7), forming chains along b, and further consolidate the structure into a three-dimensional network. The crystal packing is further strengthened by short inter-molecular O⋯O=C [2.655 (4) Å] contacts.