Dinuclear nickel(II) and palladium(II) complexes with Schiff-base ligands (derived form salicylaldehyde condensed with 2-amino-1-alcohols or from 2-hydroxy-5-methylisophthaldialdehyde and pyridine-2-carboxaldehyde condensed with semicarbazide, thiosemicarbazide, carbonodihydrazide, or thiocarbonodihydrazide) can be activated with the co-catalysts methylalumoxane (MAO) or tris(pentafluorophenyl)borane/triethylaluminium, B(C 6 F 5 ) 3 /AlEt 3 for the vinyl/addition polymerization of norbornene to reach activities of up to 2.4 · 10 7 g polymer /mol(metal)·h (molar ratios metal:Al MAO = 1:100, metal:borane:AlEt 3 = 1:9:10). Polymer characterization by GPC gave molar mass distributions of M w /M n ≈ 2, thereby indicating a coordination polymerization with a single-site character of the active species.