Unsymmetrical $eta$-diketiminato zirconium chlorides were prepared by an elimination reaction of $ZrCl_4$ with the corresponding $eta$-diketiminato lithium atoms $[Li{N(Dipp)C(R)CHC(^{t}Bu)NH}]_2$ (Dipp=$2,6-^iPr_2C_6H_3$; R=Ph or Me). Two zirconium complexes were fully characterized by elemental, $^1H$, and $^{13}C$ NMR analyses, and confirmed by single-crystal X-ray diffraction. These complexes, activated with methylaluminoxane (MAO) showed good activity towards ethylene polymerization, and produced high molecular weight polyethylene.