A simultaneous reduction of SO 4 2 - to S 2 - by 2,5-pyridinedicarboxylate under hydrothermal conditions produced a new binuclear copper(II) coordination polymer [CuS(4,4'-bipy)] n (4,4'-bipy=4,4'-bipyridine) (1). Single crystal X-ray analysis revealed that compound 1 consisted of sulfur-bridged binuclear copper(II) units with Cu-Cu bonding which were combined with 4,4'-bipy to generate a three-dimensional network constructed from mutual interpenetration of two-dimensional (6,3) nets. Crystal data for 1: C 1 0 H 8 CuN 2 S, tetragonal I4 1 /acd, a=14.0686(5)A, b=14.0686(5)A, c=38.759(2)A, Z=32. Other characterizations by elemental analysis, IR, EPR and TGA analysis were also described in this paper.