This chapter contains sections titled: Introduction Ambipolar Charge-Carrier Transport in Blends of Molecular Hole- and Electron-Conducting Materials Ambipolar Charge-Carrier Transport in Molecular Semiconductors by Applying a Passivated Insulator Surface Electrode Variation for Ambipolar and Bipolar Transport Applications of Bipolar Transport for Ambipolar and Complementary Inverters Realization of Light-Emitting Transistors with Combined Al and TTF-TCNQ Electrodes Conclusion References