In this study a novel kind of reinforcing polymethylmethacrylate (PMMA) and improving the electrical properties of polyetherimide (PEI) with a 2nd generation of layered silicates is shown. The potential of commercially available natural layered silicates seems to have reached their limitations due to small lateral dimensions and a high heterogeneity of surface charge. For example, melt compounding results mostly in incomplete delamination of the tactoids, which further reduces the maximal possible aspect ratio and therefore the desired properties. Also the incorporation of commercially available natural organo-clay in PMMA by melt-compounding leads to an increase of the stiffness, but an unsatisfactory dispersion quality of the nanoclay in the PMMA matrix leads to an decrease in toughness. Therefore reasons a newly developed kind of synthetic layered silicate was used in a transfer batch moulding process to create a PMMA-nanocomposite. With these synthetic layered silicates which have aspect ratios of up to 600, it was possible to significantly increase the young’s modulus of about 55% and the fracture toughness of about 70 %, without any decrease in tensile strength. Furthermore analysis of the corresponding fracture surfaces by scanning electron microscopy show in case of the novel filler an additional energy dissipating mechanisms like crack deflection, crack bridging as well as debonding effects with platelets pull-out leading to enhanced fracture toughness. In addition to the improvement of the mechanical behavior, the layered silicates possess the ability to decrease the coefficient of thermal expansion (CTE) of the matrix material. Therefore layered silicates provide the possibility of utilizing thermoplastic materials for applications which require a lower CTE, e.g. polymer-metal-hybrids.