Two new supramolecular compounds, 2C(6)H(9)N(2)(+). C8H4O4-.2H(2)O /(4AMPIP) (1) and C6H9N2+.C8H5O4-/(5AMPHIP) (2), were synthesized and characterized by IR spectra, (HNMR)-H-1, (CNMR)-C-13, and single-crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic system, space group Cc, with a = 7.8914(3), b = 38.4226(16), c = 7.3354(3) angstrom, beta = 107.9460(10), V = 2115.94(15) angstrom(3), D-c = 1.314g/cm(3), F(000) = 888, mu = 0.10mm(-1), Z = 4, the final R = 0.0298, and wR = 0.0835 for 3135 observed reflections with I > 2 sigma(I); and compound 2 crystallizes in the monoclinic system, space group P2(1)/c, with a = 9.0126(2), b = 12.2055(3), c = 12.3170(2) angstrom, beta = 104.2160(10)degrees, V = 1313.42(5) angstrom(3), D-c = 1.387g/cm(3), F(000) = 576, mu = 0.103mm(-1), Z = 4, the final R = 0.0454, and wR = 0.1130 for 2799 observed reflections with I > 2 sigma(I). The 2-amino-4-methylpyridinium (4AMP) and 2-amino-5-methylpyridinium (5AMP) cations are protonated at one of the pyridinium N atoms. In both compounds, the isophthalate anion interacts with protonated cations through a pair of N-HcccO hydrogen bonds to form a cyclic hydrogen-bonded motif with graph-set notation (R-2(2)(8)). In the crystal structure of 1, the ion pairs (whether cation/anion) are linked by water molecules through O-HcccO, N-HcccO, and weak C-HcccO hydrogen bonds, forming a three-dimensional network. In the crystal structure of 2, there are chains and layer made up of the O-HcccO, N-HcccO, and C-HcccO hydrogen bonds, forming a two-dimensional network.