The effects of replacing one of the 2-phenylindenyl-type ligands in bis(2-phenylindenyl)zirconium dichloride, (2-PhInd)(2)ZrCl2 (7), a catalyst precursor for the production of elastomeric polypropylene (ELPP-7), with a cyclopentadienyl-type ligand have been studied. The mixed-ring compounds: (pentamethylcyclopentadienyl) (2-phenylindenyl) zirconium dichloride, Cp*(2-PhInd)ZrCl2, (8), (pentamethylcyclopentadienyl) (1 -methyl-2-phenylindenyl) zirconium dichloride, Cp*(1-Me-2-PhInd)ZrCl2 (9), and (cyclopentadienyl) (2-phenylindenyl)zirconium dichloride, Cp(2-PhInd)ZrCl2 (10), have been synthesized through the reaction of the corresponding lithium indenide with C5R5ZrCl3 (8 and 9: R = CH3; 10: R = H). Crystal structures have been determined for complexes 8 and 9. The behavior of the catalysts derived from complexes 8, 9, and 10 upon their activation by methylaluminoxane (MAO) for ethylene and propylene polymerization has been studied. Of all mixed-ring catalysts only 8/MAO produces elastomeric polypropylene (ELPP-8) with properties consistent with a stereoblock microstructure. The stereosequence distributions in ELPP-8 determined from C-13 NMR spectra are very similar to those in elastomeric polypropylene generated with 7/MAO under comparable conditions. However, the melting points and IR indices of 8/MAO-derived samples are significantly lower than for samples of ELPP-7 with similar isotacticity which may be attributable to shorter isotactic block lengths in ELPP-8. At the same time, comparison of 8/MAO to another metallocene system capable of producing elastomeric polypropylene rac-MeHC(Me4Cp)(Ind)TiCl2/MAO, 1/MAO, described by Chien reveals significant similarities both in the catalyst symmetry and properties of generated polypropylene. The increase of isotacticity of ELPP-8 with propylene pressure similar to the trend observed for ELPP-7 favors the two-state mechanism of stereoblock formation with 8/MAO.