In this project, 4,4?-methylenebis(3-chloro-2,6-diethyl trimellitimidobenzene) as a diacid, was prepared by the reaction of trimellitic anhydride (TMA) with 4,4?-methylenebis(3-chloro-2,6-diethylaniline) (MCDEA). The novel poly(amide-imide) (PAI) was synthesized from the reaction of 4,4?-methylenebis(3-chloro-2,6-diethyl trimellitimidobenzene) as a diacid with MCDEA under green condition using molten tetra- n -butylammonium bromide (TBAB) and triphenylphosphite (TPP). Thus one equimolar of synthesized diacid with one equimolar of MCDEA was reacted at 120 °C for 12 h. The viscous reaction mixture was cooled to room temperature, and then the resulting mixture was dropped into the 20 mL of methanol to obtain polymer. The resulting PAI exhibited good yield, high thermal stability with inherent viscosity 0.48 dL/g and is soluble in polar aprotic solvents. The synthetic polymer was characterized by FT-IR, 1 H-NMR, elemental, thermogravimetric analysis (TGA) techniques, X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). Nanoparticles () are an essential material for science and technology for instance in materials, medicals, and cosmetics. Controlling the dispersion of is necessary to control the properties of the final products. Therefore the surface modification of is done by many techniques. The surface modification of TiO 2 using silane coupling agent (?-aminopropyltriethoxyl silane, KH550) and preparation of novel poly(amide-imide)/TiO 2 nanocomposites (PAI/TiO 2 NCs) by embedding of different TiO 2 contents into polymer matrix were performed via ultrasonic method as a facial and inexpensive route. The resulting NCs were characterized by FT-IR, XRD, TGA, FE-SEM and transmission electron microscopy (TEM). In the next part of the project, the surface of Nano-TiO 2 was modi?ed using bioactive diacids such as N -trimellitylimido-L-valine, N -trimellitylimido-L-leucine, N -trimellitylimido-L-alanine and N -trimellitylimido-L-methionine. For surface modi?cation of TiO 2 by diacid, TiO 2 and 15 weight percentage of diacid (as modifier) were added into methanol and were mixed at room temperature for 24 h under stirring, then the mixture of and diacid was irradiated under ultrasonic irradiation for 30 min. The modified TiO 2 was characterized by FT-IR, XRD, FE-SEM, TEM and TGA. These analyses confirmed that, this modi?cation process at room temperature was possible. The binding forms of a carboxylic group on TiO 2 may be in numerous ways, including simple adsorption (hydrogen bonding) and chemical adsorption (ester linkage). Because of these bonds between and diacid, agglomeration of is extensively reduced and the hydrophobicity of the surface of nanosized TiO 2 is obviously enhanced. The result of XRD showed that, the modi?cation of TiO 2 by diacid does not cause any alter in their peak positions compared with the pure TiO 2 . Finally Novel PAI/TiO 2 NCs were prepared by embedding of different TiO 2 contents into polymer matrix via ultrasonic method. Chiral PAI as a source of polymer matrix was synthesized by direct polycondensation reaction of N -trimellitylimido-L-valine with diaminediphenylsulphone in the presence of TPP and the TBAB. The resulting NCs were characterized by FT-IR, XRD, TGA, FE-SEM and TEM. The modified might be dispersed absolutely and will combine with PAI via the H-bonding of C=O and OH groups of diacids with –NH, C=O and SO 2 groups in PAI. Also the FE-SEM and TEM results indicated that the TiO 2 particles were dispersed homogenously in nano scale in PAI matrix.