One double chains nickel(II) coordination polymer has been synthesized and characterized in the solvent mixture of water and methanol with 3,5-dimethylbenzoic acid, 4,4' -bipyridine and nickel perchlorate anhydrous. Crystal data for this complex: Triclinic, space group PI, a=\. 134 49(12) nm, 6 = 1.137 81(12) nm, c = l.238 25(13) nm; α=100.374 0(10)°, £=109.481 0(10)°, y=101.403 0(10)°, 7=1.423 8(3) nm 3, D c = 1.314 g-cm -3, Z=l, F(000) = 592, final GooF=1.029, R 1=0.039 6, W? 2=0.1064. The complex involves two solvent molecules, two wate...