The focus of the present work is addressed to the field of organic electronics, which has attracted increasing interest for the development of flexible, large area and low cost electronic applications, from light emitting diodes to thin film transistors and solar cells. The book describes initially the application of low-frequency electronic noise spectroscopy for the characterization of organic electronic devices as an innovative and non-destructive technique. The second part is focused on the application of a well-known characterization technique, such as the admittance spectroscopy, in order to characterize the conduction and dielectric properties of a test structures based on a new organic materials for future applications in the blue organic light emitting diode and in the quantum dots polymer solar cells.