The new heterogenized zirconium phenolate complexes containing different bulky ionic liquid type amine hydrochloride substituents in ortho-position have been synthesized and characterized. The oligomerization of the ethylene was carried out with use of these complexes activated by aluminium organic compounds in heptane, toluene and chlorobenzene. In the presence of diethyl aluminium chloride these complexes show higher activity than in the presence of ethylaluminium dichloride. The distributions and composition of the obtained oligomer products depend on the nature of aluminium organic compound used. The oligomerization products consist of C4 - C18 oligomers when diethyl aluminium chloride is used as a cocatalyst. In the presence of ethylaluminium dichloride the higher branched structured oligomers (oil fraction with boiling point > 350 °C) is obtained with >75 % yield. The products are easily separated from the catalysts by simple decantation and zirconium complexes may be repeatedly reused in successive ethylene oligomerization.