Three novel 5-aminoisophthalic acid (AIP) bridged polymers [Co(C8NH5O4)(H2O)](n) (1), [Ni(C8NH5O4)(H2O)](n) (2), and [Zn(C8NH5O4)(H2O)](n) (3) were synthesized by hydrothermal reactions and characterized by IR, Raman, elemental analysis, ESR, and magnetic measurements. X-ray single-crystal analyses were carried out for [Co(C8NH5O4)(H2O)](n) (1), which crystallizes in the triclinic system, space group P (1) over bar, with a = 6.477(1) Angstrom, b = 7.130(1) Angstrom, c = 9.826(2) Angstrom, alpha = 108.9(1)degrees, beta = 93.97(3)degrees gamma = 98.82(3)degrees, and Z = 2; for [Ni(C8NH5O4)(H2O)(2)](n) (2), in the triclinic system, space group P (1) over bar, a = 6.425(1) Angstrom, b = 8.115(2) Angstrom, c = 10.146(2) Angstrom, alpha = 113.09(3)degrees, beta = 99.64(3)degrees gamma = 98.90(3)degrees, and Z = 2; and for [Zn(C8NH5O4)(H2O)](n) (3), in the monoclinic system, space group P2(1)ln, a 9.044(1) Angstrom, b = 8.264(1) Angstrom, c = 11.646(1) Angstrom, beta = 100.77(1)degrees, and Z = 4. The single X-ray diffraction studies reveal that 1 consists of an infinite honeycomb layer formed by four crystallographically independent motifs packed alternatively together; 2 consists of an infinite neutral railroad-like linear polymer, and 3 consists of infinite layers of alternating four-coordinated Zn(II) cations and AIP ligands. Finally, they are all packed into beautiful threedimensional frameworks through complicated hydrogen bonding. Antiferromagnetic and ferromagnetic behaviors were observed for 1 and 2 from the magnetic measurements.