In 2,4-diamino-6-methyl-1,3,5-triazin-1-ium (acetoguanaminium) hydrogen phthalate, C(4)H(8)N(5)(+) x C(8)H(5)O(4)(-), (I), acetoguanaminium hydrogen maleate, C(4)H(8)N(5)(+) x C(4)H(3)O(4)(-), (II), and acetoguanaminium 3-hydroxypicolinate monohydrate, C(4)H(8)N(5)(+) x C(6)H(4)NO(3)(-) x H(2)O, (III), the acetoguanaminium cations interact with the carboxylate groups of the corresponding anions via a pair of nearly parallel N-H...O hydrogen bonds, forming R(2)(2)(8) ring motifs. In (II) and (III), N-H...N base-pairing is observed, while there is none in (I). In (II), a series of fused R(3)(2)(8), R(2)(2)(8) and R(3)(2)(8) hydrogen-bonded rings plus fused R(2)(2)(8), R(6)(2)(12) and R(2)(2)(8) ring motifs occur alternately, aggregating into a supramolecular ladder-like arrangement. In (III), R(2)(2)(8) motifs occur on either side of a further ring formed by pairs of N-H...O hydrogen bonds, forming an array of three fused hydrogen-bonded rings. In (I) and (II), the anions form a typical intramolecular O-H...O hydrogen bond with graph set S(7), whereas in (III) an intramolecular hydrogen bond with graph set S(6) is formed.