A series of nickel halides bearing 2,4-di-t-butyl-6-（quinolin-8-yliminomethyl） phenolate ligands was synthesized and characterized by IR spectroscopy and elemental analysis. Molecular structures of C1 （R = H, X = Br） and C2 （R = H, X = C1） were further confirmed by single-crystal X-ray crystallographic studies, and revealed a distorted square planar geometry at nickel. Upon activation with diethylaluminum chloride （Et2AlCl）, all nickel pre-catalysts displayed good catalytic activity up to 9.3 × 10^5 g mol-1（Ni） h-1 for ethylene oligomerization with major dimerization. In the presence of methylaluminoxane （MAO）, the nickel complex C1 was capable of ethylene polymerization under 3 MPa, and produced polyethylene products with narrow polydispersity （1.16-1.73） and molecular weights in the range of 2.6-4.95 kg/mol.