A series of chromium(III) complexes bearing 2-benzoxazolyl-6-aryliminopyridines was synthesized and characterized by IR spectroscopic and CHN analysis. The X-ray crystallographic analysis of complex Cr3 revealed a distorted octahedral geometry. When activated by Et2AlCl, MAO or MMAO, these chromium complexes exhibited activities towards ethylene reactivity. High activities of ethylene oligomerization (up to 9.19 × 106 g mol−1 (Cr) h−1) were observed in the catalytic system using MMAO as a cocatalyst, meanwhile good activities of ethylene polymerization were achieved (up to 5.20 × 105 g mol−1 (Cr) h−1) by using MAO as a cocatalyst. Various reaction parameters were investigated in detail, and the steric and electronic effects of ligands were discussed.