In the present investigation, novel poly(amid-imide)/zinc oxide nanocomposites(PAI/Zn O NCs) containing benzoxazole and benzimidazole pendent groups with different amounts of modified zinc oxide nanoparticles(Zn O NPs) were successfully prepared via the ex situ method. Poly(amid-imide)(PAI) was prepared by direct polycondensation of 2-[3,5-bis(N-trimellitimidoyl)phenyl]benzoxazole(DCA) with 5-(2-benzimidazole)-1,3-phenylenediamine(DAMI) and provided the polymeric matrix with well-designed groups. The surface of Zn O NPs was functionalized with 3-aminopropyltriethoxysilane(APS) coupling agent to have a better dispersion and enhancing possible interactions of NPs with functional groups of polymer matrix. The amount of APS bonded to the Zn O surface was determined by thermogravimetric analysis. PAI/Zn O nanocomposites were characterized by Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), and scanning electron microscopy(SEM). SEM analysis showed that the modified Zn O nanoparticles were homogeneously dispersed in polymer matrix. In addition, TGA data indicated an enhancement of thermal stability of the nanocomposite compared with the neat polymer. In the present investigation, novel poly (amid-imide) / zinc oxide nanocomposites (PAI / Zn O NCs) containing benzoxazole and benzimidazole pendent groups with different amounts of modified zinc oxide nanoparticles (Zn O NPs) were successfully prepared via the ex situ method Poly (amid-imide) (PAI) was prepared by direct polycondensation of 2- [3,5-bis (N-trimellitimidoyl) phenyl] benzoxazole with 5- DAMI) and provided the polymeric matrix with well-designed groups. The surface of Zn O NPs was functionalized with 3-aminopropyltriethoxysilane (APS) coupling agent to have a better dispersion and enhancing potential interactions of NPs with functional groups of polymer matrix. The amount of APS bonded to the Zn O surface was determined by thermogravimetric analysis. PAI / Zn O nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy the modified Zn O nanoparticles were homogeneously dispersed in polymer matrix. In addition, TGA data indicated an enhancement of thermal stability of the nanocomposite compared with the neat polymer.