Abstract A series of new oxygen-substituted, asymmetric zirconocene dichlorides (rac-{1-[5, 6-(ethylenedioxy)-2-methyl-1-η 5-indenyl]-2-(9-η 5-fluorenyl) ethane} zirconium dichloride (3a), rac {1-[5, 6-(ethylenedioxy)-2-methyl-1-η 5-indenyl]-2-(9-η 5-fluorenyl) ethane} dimethylzirconium (3b) and rac-{[5, 6-ethylenedioxy)-2-methyl-1-η 5-indenyl](9-η 5-fluorenyl) dimethylsilane} zirconium dichloride (3c)} have been prepared and their polymerization ...