The aim of this work is the synthesis of new organo-clay using montmorillonite (MMT) and 1-hexadecyl-2-[(5-methyl-isoxazol-3-yl) methylbenzimidazole] cation (A3H+). The modified montmorillonite was then used for the preparation of polystyrene/clay nanocomposites. Different methods were used for the characterization of the synthesized material.