The synthesis (4a-d) and structure (4a,c) of the four crystalline, water-stable, hydrocarbon-and perfluorocarbon (PFC)-soluble fluorous zirconocene(IV) dichloride precatalysts [Zr-{η 5-C 5 H 4 SiMe 3-n (R F) n } 2 Cl 2 ] (n) 1, R F) CH 2 CH 2 C 6 F 13 (4a), C 8 F 17 (4b), CH 2 C 6 F 5 (4c); n) 3, R F) CH 2 C 6 F 5 (4d)), possessing one to three fluorous alkyl or aryl groups attached to the cyclopentadienyl ligand through a silicon atom and an additional methylene (4c,d) or ethylene (4a) spacer or no spacer at all (4b), are reported. A nonfluorous analogue of 4a, [Zr{η 5-C 5 H 4-SiMe 2 C 8 H 17 } 2 Cl 2 ] (4e), was prepared for comparison, and 4a was easily converted to its dimethyl derivative [Zr{η 5-C 5 H 4 SiMe 2 CH 2 CH 2 C 6 F 13 } 2 Me 2 ] (5a). The ethylene polymerization activities of the zirconocene dichlorides were compared to those of the known bis-{(trimethylsilyl)cyclopentadienyl}zirconium dichloride [Zr{η 5-C 5 H 4 SiMe 3 } 2 Cl 2 ] (4f), in both toluene and fluorous biphasic solvent (FBS) systems. In the case of 4b a PE with a bimodal molecular weight distribution and a significantly lower molecular weight was obtained. Polymerization data and polymer properties for 4a-d, compared to data for 4f, show a marked influence of the fluorous groups and the alkyl spacer (e.g. methylene in 4c or ethylene in 4a). FBS conditions result in PE with a higher average molecular weight. Evidence on the nature of the active species formed when these precatalysts were treated with an excess of methylaluminoxane (MAO) is presented.