Treatment of dimethyl(tetramethylcyclopentadienyl)chloro silane with S-(-)pyrrolidine methanol provided the O-silylated ligand (C 5 Me 4 H)SiMe 2 OCH 2 (C 4 H 7 NH), 1, (Cp * SiProH 2 ) as a 90% pure, thermally unstable oil in 65% yield. Reaction of 1 with Zr(NMe 2 ) 4 resulted in attachment of 1 to the zirconium center with elimination of HNMe 2 , yielding (Cp * SiPro)Zr(NMe 2 ) 2 , 2, as a viscous oil in high yield (95%). Compound 2 was converted to the trichloride derivative (Cp * SiProH)ZrCl 3 , 3, in 75% yield by treatment with three equivalents of HCl HNMe 2 : compound 3 is produced as a mixture of diastereomers; the major species was characterized by X-ray crystallography, revealing a Cp * --O--N coordination mode for the Cp * SiProH ligand. (3: orthorhombic, space group P2 1 2 1 2 1 , a = 10.0009(13), b = 12.7597(12), c = 16.2749(15) , V = 2076.8(4) 3 , Z = 4,R = 0.043, R w = 0.041.) Deprotonation of 3 (diastereomeric mixture) with LiN(SiMe 3 ) 2 produced the dichloride (Cp * SiPro)ZrCl 2 , 4, in 71% yield. Alkylation of either 3 or 4 resulted in Si--O bond cleavage in the Cp * SiPro ligand and gave a dimeric complex5 which was characterized by X-ray crystallography. (5: monoclinic, space group P2 1 ,a = 9.1285(10), b = 20.2197(22), c = 11.0214(14) , β = 90.38(7)°, V = 2034.2(4) 3 ,Z = 2, R = 0.040, R w = 0.042.) Limited ethylene polymerization activity was observed for3 and 4 in the presence of MAO co-catalyst.