Two new transition-metal organic coordination polymers [M(mna)₂] (M = Cd (1), Zn (2); mna = 2-mercaptonicotinic anion) have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction along with IR and elemental analyses. Compound 1 is generally a one-dimensional linear structure bridged through the sulfur donor of mna ligand, while 2 is a one-dimensional zigzag chain ligated via the oxygen donor of mna ligand. These compounds further result in three-dimensional structures via intermolecular π…π stacking interactions and/or hydrogen bonding interactions. The two compounds were structurally determined by single-crystal X-ray diffraction. Complex 1 crystallizes in monoclinic space group P2₁/c with a = 3.730(3), b = 13.973(12), c = 12.380(11) Å, β = 97.953(18)°, V = 639.0(10) ų, Z = 2, CdC₁₂H₈O₄N₂S₂, M_r = 420.72, D_c = 2.187 g/cm³, F(000) = 412, R_int = 0.0252, T = 293(2) K, μ = 2.052 mm^-1, the final R = 0.0269 and wR = 0.0586 for 1377 observed reflections with I > 2σ(I). Complex 2 belongs to monoclinic space group P2₁/c with a = 13.376(2), b = 12.8429(14), c = 7.4856(10) Å, β = 96.190(10)°, V = 1278.5(3) ų, Z = 4, ZnC₁₂H₈O₄N₂S₂, M_r = 373.69, D_c = 1.941 g/cm³, F(000) = 752, R_int = 0.0414, T = 293(2) K, μ = 2.264 mm^-1, the final R = 0.0418 and wR = 0.0966 for 2396 observed reflections with I > 2σ(I).