This invention relates to compounds represented by formula: ##STR00001## wherein M is a group 3, 4, 5 or 6 transition, lanthanide, or actinide metal atom; E is an indenyl ligand substituted in any position with at least one aromatic or pseudoaromatic heterocyclic substituent that is bonded to the indenyl ring through a nitrogen or phosphorous ring heteroatom; A is a substituted or unsubstituted cyclopentadienyl, heterocyclopentadienyl, indenyl, heteroindenyl, fluorenyl, or heterofluorenyl ligand, or other mono-anionic ligand, or A may, independently, be E; Y is an optional bridging group; y is zero or one; X are, independently, univalent anionic ligands, and provided that when A is E, and y is one, and Y is bonded to the one position of each indenyl ligand, and per indenyl ligand there is only one aromatic heterocyclic or pseudoaromatic heterocyclic that is bonded to the indenyl ligand.