Embodiments of the present disclosure are directed towards bicyclic hafnium metallocenes having non-identical ligands and compositions including the bicyclic hafnium metallocenes having non-identical ligands. The bicyclic hafnium metallocene having non-identical ligands is represented by formula (I): ABMX2, where: A is a bicyclic structure; and B is a cyclopentadienyl; M is hafnium; and X is a leaving group, wherein the bicyclic structure comprises a ((C1-C6)alkyl)n-substituted Cp ring and a non-aromatic cyclic structure fused with the ((C1-C6) alkyl)n-substituted Cp ring such that the bicyclic structure includes 7 to 9 ring carbon atoms and wherein subscript n is 1, 2, or 3.