To improve the thermal and mechanical properties of polyimides, a nanocomposite ofnaphthalene containing polyimide (PI) was hybridized with Montmorillonite (MMT). The PI wassynthesized from a diamine, 2,7-bis (4-aminophenoxy) naphthalene and polymerized with a3,3’,4,4’-benzophenone tetracarboxylic dianhydride via thermal imidization. PI-MMTnanocomposites were then prepared from a DMAc solution of poly(amic acid) precursor and a DMAcdispersion of MMT which were organo-modified with various amount of n-dodecylamine.Characterization results demonstrated that the introduction of a small amount of MMT (up to 5%) ledto enhanced thermal stability and mechanical properties of PI. The 5% weight loss temperature in N2was increased by 46oC in comparison to pristine PI with an organoclay content of 5%. The CTE anddielectric constant were decreased. However, at organoclay contents higher than 5% these propertieswere reduced because the organoclay was poorly dispersed and resulted in aggregate formation.