A series of new indanimine ligands [ArN=CC2H3(CH3)C6H2(R)OH] (Ar = Ph, R = Me (1), R = H (2), and R = C1 (3); Ar = 2,6-i-Pr2C6H3, R = Me (4), R = H (5), and R = Cl (6)) were synthesized and characterized. Reaction of indanimines with Ni(OAc)(2).4H(2)O results in the formation of the trinuclear hexa(indaniminato)tri (nickel(II)) complexes Ni-3[ArN = CC2H3(CH3)C6H2(R)O](6) (Ar = Ph, R = Me (7), R = H (8), and R = Cl (9)) and the mononuclear bis(indaniminato)nickel (II) complexes Ni[ArN=CC2H3(CH3)C6H2(R)O](2) (Ar = 2,6-i-Pr2C3H3, R = Me (10), R = H (11), and R = Cl (12)). All nickel complexes were characterized by their IR, NMR spectra, and elemental analyses. In addition, X-ray structure analyses were performed for complexes 7, 10, 11, and 12. After being activated with methylaluminoxane (MAO), these nickel(II) complexes can polymerize norbornene to produce addition-type polynorbornene (PNB) with high molecular weight M-v (10(6) g mol(-1)), highly catalytic activities up to 2.18 X 10(7) gPNB mol(-1) Ni h(-1). Catalytic activities and the molecular weight of PNB have been investigated for various reaction conditions. (C) 2007 Wiley Periodicals, Inc.