Two-dimensional hydrogen-bonded supra­molecular networks in the compounds of benzene-1,2,4,5-tetra­carb­oxy­lic acid (pyromellitic acid) with 2,2'-bi­imidazole and 4,4'-di­methyl-2,2'-bi­pyridine

Two salts obtained from the proton-transfer reactions of benzene-1,2,4,5-tetra­carb­oxy­lic acid (pyromellitic acid, PMA) with 2,2'-bi­imidazole and 4,4'-dimethyl-2,2'-bipyridine form one-dimensional O-H...O hydrogen-bonded chain structures extended into two-dimensional supra­molecular layers and sheets via O-H...O and N-H...O hydrogen bonding.