In the anion of the title molecular salt, C(6)H(9)BNO(2) (+)·C(7)H(4)NO(4) (-), the dihedral angles between the -COO(2-) and -CO(2)H groups and their attached ring are 4.02 (13) and 21.41 (10)°, respectively. The B atom in the cation adopts a syn-syn geometry and the dihedral angle between the -B(OH)(2) group and its attached ring is 11.06 (5)°. In the crystal, O-H⋯O, N-H⋯O and N-H⋯N hydrogen bonds link the components into a three-dimensional network.