Ferricenium and ferrocene ammonium-modified clays have been prepared and used to produce nanocomposites of polystyrene by melt blending and bulk polymerization. The type of nanocomposites has been characterized by X-ray diffraction (XRD), cone calorimetry, thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). TGA data show that the thermal stability of all the nanocomposites is improved. When two long alkyl chains are present on the cation of the clay, the properties of the nanocomposites are enhanced. Fire properties of these ferrocene ammonium and ferricenium nanocomposites have also been examined. These systems do give clays that have good thermal stability and may be useful for melt blending with polymers that must be processed at higher temperature.