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

In the title compound, 2C 7 H 7 N 2 O + ·C 2 O 4 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.