2-Amino-benzoxazole-oxalic acid (2/1).

In the title compound, 2C7H7N2O+·C2O4 2-, proton transfer from oxalic acid to the N atom of the heterocycle has occurred to form a 2:1 molecular salt. In the extended structure, N-H⋯O hydrogen bonds link the components into [100] chains, which feature R 2 2(8) and R 4 4(14) loops.