Currently, resource efficiency and CO2-reduction are getting more important in industrial production, especially in the automotive sector. To achieve this goal, automotive industries are exploring the methods to produce weight-reduced components (lightweight) without sacrificing its mechanical properties as it directly influences the safety of the occupant. Lightweight design with hybrid systems enables weight saving and performance increase with a function integration and mechanical property enhancement. Combining the process steps of forming and joining the constituents of the hybrid system reduces cycle time and manufacturing costs. Compression molding is one of the promising process that can be optimized so that the forming and joining can be combined. In general, conventional in-mold assembly (IMA) processes combine a reinforcing (rib) structure of fiber-reinforced plastics (FRP) with a metal component in two manufacturing stages. An innovative IMA process for hybrid bending structures has been developed in which glass-mat-reinforced thermoplastic (GMT) is formed and joined between two metal belts by compression molding in one manufacturing stage. The GMT core rib structure transmits load between the metal belts and fulfills stiffening, reinforcing and functional purposes. The metal belts bear high tensile and compressive loads. This innovative one stage manufacturing process can produce complex hybrid structures with load-adapted material distribution and a high degree of function integration. Selection of the appropriate bonding technique between GMT and steel is studied in the current project. The process is then validated by producing hybrid brake pedals and testing them under static conditions.