New bridging ligand, 2,6-diphenylbenzo[1,2-d:4,5-d']bisthiazoline, have been synthesized by reaction of 2,5-diamino-1,4-benzenethiol dihydrochloride with benzaldehyde in a 1:2 stoichiometry. Reaction of this ligand with nickel(II) acetate tetrahydrate gave some nickel(II) complexes which show a strong near-infrared absorption due to extended pi-conjugation. Structural assignment of two complexes was made on the basis of IR and electronic spectroscopic studies as well as elemental analyses.