Tetra­methyl­pyrazine–endo-norbornene-cis-5,6-di­carboxyl­ic acid (1/2)

In the title complex, 2C9H10O4·C8H12N2, there is an inversion centre at the centre of the 2,3,5,6-tetra­methyl­pyrazine mol­ecule, which is linked to two endo-norbornene-cis-5,6-di­carboxyl­ic acid mol­ecules via O—H⋯N hydrogen bonds. In the crystal structure, O—H⋯O and O—H⋯N hydrogen bonds propagate a one-dimensional zigzag chain, which is extended into layers when combined with longer C—H⋯O hydrogen bonds.