A synthetic method was developed to produce N,N’-dimethylated diamines which were then used to prepare poly(imide amide)s. Thus, N,N’-dimethyl-4,4’-bis(4-aminophenoxy)biphenyl and N,N’-dimethyl-2,2-bis(4-aminophenyl)hexafluoropropane were condensed at 0 degrees C in dimethylacetamide with 2,2-bis[N-(4-chlorocarboxyphenyl)phthalimidyl]hexafluoropropane. The yields were 76-92%, viscosities 0.28-2.26 dl g(-1), water absorptions 0.16-0.37 wt% and thermal stabilities around 460 degrees C by thermogravimetric analysis. The addition of the methyl group caused lower molecular weights but superior thermal stability (isothermally) and decreased colour.