A series of 8-(2,6-dibenzhydryl-4-R-phenylimino)-5,6,7-trihydroquinoline ligands have been prepared in which the nature of 4-R substitutions vary from electron withdrawing to electron donating. The treatment with NiCl2.6H(2)O or (DME)NiBr2 afforded the corresponding complexes of nickel chloride (4-R=Me Ni1, Et Ni2, Bu-t Ni3, CHPh2 Ni4, Cl Ni5, and F Ni6) and nickel bromide (4-R=Me Ni7, Et Ni8, Bu-t Ni9, CHPh2 Ni10, Cl Ni11, and F Ni12). X-ray diffraction study of complexes Ni3, Ni6, and Ni10, revealed that Ni3.1/2H(2)O and Ni6.H2O adopted unsymmetrical and symmetrical chloride-bridged dinuclear structures respectively, while Ni10.H2O is found as mononuclear specie forming distorted-square planer geometry. In the presence of either diethylaluminum chloride (Et2AlCl) or modified methylaluminoxane (MMAO), all the nickel complexes (Ni1-Ni12) displayed high activities (up to 1.91 x 10(6) g(PE) mol (Ni)(-1)h(-1). Highly branched polyethylene waxes with low molecular weights (M(w)2.6 kg/mol) and narrow molecular weights distributions (M-w/M(n)1.96) incorporated with vinylene and vinyl groups were obtained. The effects of 4-R substitutions to the nickel chloride and bromide pre-catalysts and reaction conditions on the catalytic performance and the properties of the resulting polyethylene were the subject of a detail investigation. The positive influences of using electron-withdrawing 4-R substitutions and bromides were observed. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1269-1281