Three-dimensional networks in the 1:2 organic salts 2,2'-biimidazolium bis(3-carboxy-4-hydroxybenzenesulfonate) and 2,2'-bibenzimidazolium bis(3-carboxy-4-hydroxybenzenesulfonate) trihydrate.

The two title compounds of 2,2'-biimidazole (Bim) with 5-sulfosalicylic acid (5-H(2)SSA) and 2,2'-bibenzimidazole (Bbim) with 5-H(2)SSA are 1:2 organic salts, viz. C(6)H(8)N(4)(2+).2C(7)H(5)O(6)S(-), (I), and C(14)H(12)N(4)(2+).