Lanthanide coordination polymers were synthesized from Pr(III), Nd(III), and Gd(III) salts; 2-hydroxynicotinic acid (Hnica); and MnSO4 center dot H2O under hydrothermal conditions. In the absence of (CH3)(3)CCOONa, 1D polymers with an infinite Ln(III)-O-Ln(III) chain structure, (Pr(Hnica)(H2O)(2)SO4](n), (1), [Nd(Hnica)(H2O)(2)SO4](n) (2), and [Gd(Hnica)(H2O)(2)SO4](n) (3), were generated. When (CH3)(3)CCOONa was added to the synthetic systems, 2D coordination polymers {[Pr-3(Hnica)(6)(H2O)(9)]center dot 3H(2)O center dot SO4 center dot NO3}(n) (4), [[Nd-3(Hnica)(6)(H2O)9]center dot 3H(2)O center dot SO4 center dot NO3}(n) (5), and {[Gd(Hnica)(2)(H2O)(2)]ClO4 center dot H2O}(n), (6) were obtained. Complexes 4 and 5 both exhibit Kagome lattice structure, while 6 displays a rhombic grid structure. All complexes were characterized by elemental analysis, IR spectra, UV-vis spectra, and X-ray single-crystal diffraction. The variable-temperature magnetic susceptibility studies reveal ferromagnetic interactions between gadolinium(III) ions in 3 and 6 and antiferromagnetic interactions in 1, 2, 4, and 5.