High temperature resistant polymers like Polyarylethers (PESU: Polyethersulfone, PSU: Polysulfone) offer high modulus over a wide temperature range, near to their Tg´s. This can be a significant advantage in applications, where metals have to be replaced by easy processible lightweight materials. In our presentation, different approaches to new materials offering high temperature resistance and high modulus at elevated temperature are presented. To achieve high stiffness, the thermoplastic matrix has to be reinforced by either carbon or glass fibres. For metal replacement in particular, tensile moduli larger than 10 GPa at 120°C are requested. Such values can usually not be achieved using the existing semi-crystalline matrices like PPS or PPA, since due to their low Tg´s (90°C or 130°C respectively) such compounds show a significant loss of performance at temperatures around or exceeding their Tg´s. Therefore, to achieve such level of performance amorphous matrix materials like Polyethersulfone have to be combined with high fibre loading. On the other hand, amorphous high temperature polymers usually have a comparatively high melt viscosity, which is a limiting factor for the preparation of compounds with high fibre loading. By a clever combination of existing polymer components, materials based on Polyethersulfone having excellent thermal resistance, high dimensional stability and tensile moduli exceeding 10 GPa at 120°C can be obtained.