Palladium catalysts [(ArN=C(Me)—C(Me)=NAr)Pd(CH2)3(COOMe)]+BAr′–4 (VERSIPOLTM) and [(ArN=C(Me)—C(Me)=NAr)Pd(CH2)3(COOMe)]+BF4– (Ar=2,6-i-Pr2—C6H3 and Ar′=3,5-(CF3)2—C6H3) were used to polymerize olefins or to copolymerize ethylene with various polar comonomers including macromonomers. The most important contribution of the present work deals with the influence of the polymerization conditions on the structure of the resulting poly(olefins). Dilute solution characterization of poly(ethylene)s by light scattering, intrinsic viscosimetry and SEC techniques on line with light scattering revealed strong differences between structural parameters of samples prepared under almost identical conditions except ethylene pressure. The copolymerization of ethylene with polar monomers was also examined and the results compared to existing data. Special attention was devoted to the case of benzyl acrylate. For methyl (meth)acrylates or related monomers earlier results could be confirmed in most cases. Preliminary attempts to copolymerize ethylene with allyl end-capped polystyrene macromonomers have been performed giving access to a new type of graft copolymer aimed to serve as compatibilizers.