A series of iron complexes ligated by 2-imino-1,10-phenanthrolinyl ligands, LFeCl
2 (L = 2-(ArN=CR)-1,10-phen), were synthesized and sufficiently characterized by elemental and spectroscopic analysisalong with X-ray diffraction analysis. Activated with methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), these iron(II) complexes show high catalytic activities up to 8.95 × 10
7 g mol
-1(Fe)h
-1 for ethylene oligomerization. The distribution of oligomers produced follows Schluz-Flory ruleswith high selectivity for
-olefins. Both the steric and electronic effects of coordinative ligands affectthe catalytic activity and the properties of the catalytic products. The parameters of the reaction conditionswere also investigated to explore the catalytic potentials of these complexes.