A series of allylated α-diimine complexes of Ti, Zr, V, Cr, Fe, Ni, and Pd was prepared and characterized. These complexes were activated with methylaluminoxane (MAO) and tested for catalytic ethylene polymerization. The allyl groups of the ligands can self-immobilize the catalysts and prevent reactor fouling. The catalyst activities and the properties of the obtained polyethylenes are influenced by the metal center and the structure of the corresponding catalyst. The allylated α-diimine nickel catalysts showed the highest activities in the series and produced polyethylenes with higher molecular weights compared to the analogous catalysts without allyl groups. The allylated α-diimine palladium catalysts showed no activities for ethylene polymerization.