An olefin polymerization catalyst system comprising a procatalyst component chosen from metal-ligand complexes according to Formula (I): where: M is titanium, zirconium, or hafnium; each X is independently a monodentate or polydentate ligand that is neutral, monoanionic, or dianionic; n is an integer; the metal-ligand complex of Formula (I) is overall charge-neutral; each of Y 1-4 is independently selected from C or N with the proviso that exactly one of Y 1-4 is N or exactly two of Y 1-4 are N; each of Y 7-10 is independently selected from C or N with the proviso that exactly one of Y 7-10 is N or exactly two of Y 7-10 are N; Rand R 10 are both independently selected from the group consisting of (C 1 -C 40 ) hydrocarbyl, substituted (C 1 -C 40 ) hydrocarbyl, (C 1 -C 40 ) heterohydrocarbyl, substituted (C 1 -C 40 ) heterohydrocarbyl, and an electron pair; each of R 2 , R 3 , R 4 , R 7 , R 8 , and R 9 is independently selected from the group consisting of hydrogen, (C 1 -C 40 ) hydrocarbyl, substituted (C 1 -C 40 ) hydrocarbyl, (C 1 -C 40 ) heterohydrocarbyl, substituted (C 1 -C 40 ) heterohydrocarbyl, halogen, nitro, and an electron pair; and R 5 and R 6 are both independently selected from the group consisting of (C 1 -C 40 ) hydrocarbyl, substituted (C 1 -C 40 ) hydrocarbyl, (C 1 -C 40 ) heterohydrocarbyl, and substituted (C 1 -C 40 ) heterohydrocarbyl; any two or more of R 1-5 optionally may be taken together to form at least one ring structure having from 5 to 16 atoms in the ring excluding any hydrogen atoms; any two or more of R 6-10 optionally may be taken together to form at least one ring structure having from 5 to 16 atoms in the ring excluding any hydrogen atoms; and any two or more of R 1-10 optionally may be taken together to form a linked tetradentate chelant structure. M is titanium, zirconium, or hafnium; each X is independently a monodentate or polydentate ligand that is neutral, monoanionic, or dianionic; n is an integer; the metal-ligand complex of Formula (I) is overall charge-neutral; each of Y 1-4 is independently selected from C or N with the proviso that exactly one of Y 1-4 is N or exactly two of Y 1-4 are N; each of Y 7-10 is independently selected from C or N with the proviso that exactly one of Y 7-10 is N or exactly two of Y 7-10 are N; Rand R 10 are both independently selected from the group consisting of (C 1 -C 40 ) hydrocarbyl, substituted (C 1 -C 40 ) hydrocarbyl, (C 1 -C 40 ) heterohydrocarbyl, substituted (C 1 -C 40 ) heterohydrocarbyl, and an electron pair; each of R 2 , R 3 , R 4 , R 7 , R 8 , and R 9 is independently selected from the group consisting of hydrogen, (C 1 -C 40 ) hydrocarbyl, substituted (C 1 -C 40 ) hydrocarbyl, (C 1 -C 40 ) heterohydrocarbyl, substituted (C 1 -C 40 ) heterohydrocarbyl, halogen, nitro, and an electron pair; and R 5 and R 6 are both independently selected from the group consisting of (C 1 -C 40 ) hydrocarbyl, substituted (C 1 -C 40 ) hydrocarbyl, (C 1 -C 40 ) heterohydrocarbyl, and substituted (C 1 -C 40 ) heterohydrocarbyl; any two or more of R 1-5 optionally may be taken together to form at least one ring structure having from 5 to 16 atoms in the ring excluding any hydrogen atoms; any two or more of R 6-10 optionally may be taken together to form at least one ring structure having from 5 to 16 atoms in the ring excluding any hydrogen atoms; and any two or more of R 1-10 optionally may be taken together to form a linked tetradentate chelant structure. <EOS>