Ten examples of nickel(II) halide complexes [8-{N(2,4-(C 15 H 13 ) 2 -6-RC 6 H 2 N)}C 9 H 8 N]NiBr 2 [R = Me (Ni1), Et (Ni2), iPr (Ni3), Cl (Ni4), or F (Ni5)] and [8-{N(2,4-(C 15 H 13 ) 2 -6-RC 6 H 2 N)}C 9 H 8 N]NiCl 2 [R = Me (Ni6), Et (Ni7), iPr (Ni8), Cl (Ni9), or F (Ni10)], each incorporating a sterically encumbered N,N-chelating 8-[2,4-bis(dibenzocycloheptyl)-6-R-phenylimino]-5,6,7-trihydroquinoline ligand, are disclosed. Full details for the preparation of these complexes as well as the zinc-mediated synthesis of precursor ligands L1−L5 are given. Structural characterization of Ni3(H 2 O), Ni6, Ni7(H 2 O), and Ni8(H 2 O) reveals halide-bridged dinuclear structures of the type (N,N)NiX(μ-X) 2 NiX(N,N) with the ortho-substituted dibenzocycloheptyl groups providing steric protection to each metal center. In the presence of ethylaluminum dichloride (EtAlCl 2 ) or methylaluminoxane (MAO), Ni1−Ni10 displayed high activities for ethylene polymerization [≤6.17 × 10 6 g of PE (mol of Ni) −1 h −1 for Ni6/EtAlCl 2 at 20 °C], generating low-molecular weight polyethylene waxes. Notably, catalysts incorporating a 6-alkyl group (Me, Et, or iPr) as the N-aryl substituent proved to be more active than their 6-halide (Cl or F) counterparts and formed relatively higher-molecular weight polymers (M w range of 9.1−22.9 kg mol −1 ) with a narrow dispersity. Moreover, analysis of these waxes by 13 C nuclear magnetic resonance spectroscopy showed that they typically possessed short chain branching (>83% methyl) with branching densities of 79−90 branches per 1000 Cs. In addition, chain end analysis revealed the presence of both vinyl (−CH�CH 2 ) and internal vinylene (−CH�CH−) functional groups, highlighting the role of both β-H elimination and isomerization.