A new 3d-4f heterometallic polymer {[Sm2Cu(PDC)(2)(SO4)(2)(H2O)(6)]center dot 2H(2)O}(n) 1 has been synthesized by Sm2O3, Cu(SO4)(2)center dot 5H(2)O and pyridine-3,5-dicarboxylic acid under hydrothermal conditions. The compound crystallizes in triclinic system, space group P (1) over bar, with a = 6.352(7), b = 10.040(10), c = 10.315(11) angstrom, alpha = 94.958(14), beta = 95.556(7), gamma = 99.747(14)degrees, V = 641.7(12) angstrom(3), Z = 1, M-r = 1030.63, D-c = 2.651 Mg/m(3), mu = 5.615 mm(-1), F(000) = 491, the final R = 0.0491 and wR = 0.1345 for 2098 observed reflections with I > 2 sigma(I). The compound is a three-dimensional network structure in which infinite lanthanide-carboxylate chains are linked by [Cu(SO4)(2)](2-) metalloligands to form a mixed-metal coordination network.