A novel nickel(Ⅱ) complex(1) containing dithiolate ligand was synthesized by reaction of 5,8,11,14-tetraoxa-2,17,19,21-tetrathiabicy-clo［16.3.0］heneicosa-1(18)-en-20-one with Ni(dbbpy)Cl₂(dbbpy=4,4′-di-tert-butyl-2,2′-bipyridine) in solution of CsOH and MeOH/THF. The structure was characterized by ¹H NMR, IR, MS and elemental analysis. 1 exhibited a significant response for Na⁺ with △E1^1/2 of 100 mV(20 times of Na⁺) and 125 mV(30 times of Na⁺), and displayed solvatochromic behavior at room temperature. 1 was very sensitive in detecting Na⁺ with an obvious change in color.