Non-coordinating anions or anion precursors are disclosed. These non-coordinating anions serve as the activator for olefin polymerization catalyst systems. As such, they abstract an alkyl leaving group from a metallocene catalyst precursor leaving an activated catalyst charge balanced by a non-coordinating anion. These anions are formed by 3 or 4 partially fluorinated naphthyl ligands coordinated around boron (or other Group-13 element) creating corresponding tris-borane or tetrakis-borate complexes.