Covering all the major types of conjugated polymers used in emerging organic electronic technologies, this guide provides the fundamental chemistry and physics, and shows how to design materials with optimal performance for various applications, such as in transistors, LEDs, and solar cells. The principles of molecular design are discussed, as well as a range of synthetic methods, which are linked to practical examples such as the suppression of long wavelength emission from blue-emitting polymers, the production of regioregular polythiophenes for enhanced mobility, and the development of donor-acceptor copolymers for high efficiency solar cells. Structure-property relationships are also covered, in addition to how impurities or defects can affect performance and how the devices operate. This is an indispensable reference for anyone working with or studying conjugated polymers or organic electronics.