Not long ago, it was hard to imagine that there could be any use for polymers beyond plastic bags or electrical insulators etc. With the discovery of organic semiconductors this view has changed completely: The field of organic (opto-)electronics was born and has matured significantly in recent years. First products, like displays based on organic light emitting diodes (OLEDs) and organic solar cells have already entered the market. Organic semiconductors allow for an essentially novel class of electronics, that can be light weight, highly efficient, flexible, and even transparent. This lecture will provide an introduction to the exciting field of organic semiconductors and devices. In practical courses, you will have the opportunity to fabricate and characterize organic devices (e.g. TFTs, solar cells, ...) in our lab.