Thin films, in the range of tens of micrometers thickness, have been prepared by casting onto glass plates the N-methyl-2-pyrrolidone solutions of two poly(ether imide)s containing isopropylidene or hexafluoroisopropylidene groups. The polymers have been synthesized by solution polycondensation reaction of 4,4'-(1,3-phenylenedioxy)dianiline, with 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride or 1,1,1,3,3,3-hexafluoro-2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride. The dynamic mechanical analysis and dielectric spectroscopy were employed to study thermal and electrical behaviour of polymer films.