The goal of the present project is to investigate novel device concepts based on organic semiconductor materials: the number of device principles is still rather small for organic devices and many concepts are not explored. The concept of controlled molecular doping successfully introduced to optoelectronic devices will be used here to achieve Fermi level control and well-defined junctions. Preferentially, we plan to work in this project with oligomer substances which are deposited by vacuum technology. The main reason for this choice is that this approach allows depositing multilayer structures with comparatively high reproducibility. However, the principles developed here should also applicable with other low-cost deposition technologies such as printing. Based on previous experiments such as the realization of the first pn-homojunction, this work will concentrate on the following devices: First, we want to further develop the Zener diodes which have in first experiments shown that the basic effects exist in organic devices as well. The goal is to significantly reduce the forward offset voltage and the improve controllability of the reverse breakdown voltage. Second, we want to try to realizeefficient triodes allowing larger currents and higher switching speed as conventional approaches. Furthermore, we strive to realize an organic bipolar transistor, which is challenging in organic devices due the rather small diffusion lengths. Third, we will approach new devices with more complex layer structures, such as thyristors. While certain device types will be in the focus of the projects, we expect that the general understanding of organic semiconductors in switching device applications can be improved.