This review deals with recent progress on the development of nanocomposite materials formed by conducting organic polymers (COPs) and carbon nanotubes (CNs), both from a fundamental and applied point of view. The combination of the unique properties of CNs with COPs makes of these materials interesting multifunctional systems with great potential in many applications such as supercapacitors, sensors, photovoltaic cells and photodiodes, optical limiting devices, solar cells, high-resolution printable conductor, electromagnetic absorbers, and, last but not least, advanced transistors.