The alkylation of the Brookhart-Gibson {2,6-[2,6-(i-Pr)(2)PhN=C(CH3)](2)(C5H3N)} FeCl2 precatalyst with 2 equiv of LiCH2Si(CH3)(3) led to the isolation of several catalytically very active products depending on the reaction conditions. The expected dialkylated species {2,6-[2,6-(i-Pr)2PhN=C(CH3)](2)](C5H3N)Fe(CH2-SiMe3)(2) (2) was indeed the major component of the reaction mixture. However, other species in which alkylation occurred at the pyridine ring ortho position, {2,6-[2,6-(i-Pr)(2)PhN=C(CH3)](2)-2-CH2SiMe3}(C5H3N)Fe(CH2SiMe3) (1), and at the imine C atom, {2-[2,6-(i-Pr)(2)PhN=C(CH3)]-6-[2,6-(i-Pr)(2)PhNC(CH3)(CH2 SiMe3)](C5H3N)}Fe(CH2SiMe3) (3), have also been isolated and fully characterized. In addition, deprotonation of the methyl-imino functions and formation of a new divalent Fe catalyst 1[2,6-[2,6-(i-Pr)(2)PhNC=(CH2)](2)(C5H3N)}Fe(mu-Cl)Li(THF)(3) (4) also occurred depending on the reaction conditions. In turn, the formation of 4 might trigger the reductive coupling of two units through the methyl-carbon wings. This process resulted in the one-electron reduction of the metal center, affording a dinuclear Fe(I) alkyl catalyst 1[1[2,6(i-Pr)(2)C6H5]N=C(CH3)](C5H3N) f [2,6-(i-Pr)(2)C6H5]N=CCH2}Fe(CH2SiMe3)]}2 (5). Different from other metal derivatives, complex 5 could not be prepared from the monodeprotonated version of the ligand. Its reaction with a mixture of FeCl2 and RLi afforded instead [12,6-[2,6-(i-Pr)(2)PhN-C=(CH2)](2)(C5H3N)}FeCH2Si(CH3)(3)][Li(THF)(4)] (6) which is also catalytically active. All of these high-spin species have been shown to have high catalytic activity for olefin polymerization, producing polymers of two distinct natures, depending on the formal oxidation state of the metal center.