In this research work, 1,4-bis(2,6-diisopropylphenyl)-acenaphthenediimine-diboromonickel(II) (1) complex was synthesized and its ethylene polymerization in the presence of triisobutylaluminum (TIBA) as activator was studied. The effects of three critical factors [polymerization temperature (T), cocatalyst to catalyst ratio (CC) and pressure (P)] on the average molecular weight and crystallinity of the final polymers and also reaction yields as the response variables were evaluated with the help of empirical statistical models and visualized with the response surface method. The results show that activity of 1 as well as M (w) and crystallinity of the resulting polymers are influenced strongly by the polymerization factors. The activity of TIBA-activated catalyst 1 reaches a maximum at 10 A degrees C after raising pressure and CC to 7 bar and 3,000, respectively. This activity is much higher than previously reported activity for this catalyst. Furthermore, a polymerization condition for reaching desirable responses is predicted and experimentally verified.