An oil-soluble alkyl substituted hydroxyaromatic compound, wherein the alkyl-moiety of the aromatic compounds is derived from at least one ethylene alpha-olefin copolymer of greater or above 25,000 to about 5000,000 number average molecular weight, said copolymer containing from 30 to 80 weight percent ethylene and wherein at least about 30% of the polymer's chains contain terminal ethenylidene unsaturation. The Mannich Base condensates of this invention are useful as multifunctional viscosity index improvers for oleaginous compositions, particularly lubricating oil compositions.