Polyimides based on 4,4＇-(hexafluoroisopropylidene)diphthalic anhydride and 4,4＇-(hexafluoroisopropylidene)dianiline with controlled and uncontrolled molecular weight were prepared. The products with controlled molecular weight were terminated with 4-tert-butylaniline. The synthesized poly(amic acid)s were transformed into polyimides using both thermal solid state and solution imidization. Molecular parameters of the prepared polymers were evaluated by viscometry, size exclusion chromatography and n.m.r. spectroscopy. The properties of polyimides prepared by both methods were compared.