History of the research of molecular conductors is well described as development of highly conducting materials, and actually produced organic metals and superconductors. Study of organic superconductors led us to the physics of correlated electrons such as Mott insulators and charge order. A charge-ordered material exhibited remarkable nonlinear conductivity and functions as an electronic device, and is called an organic thyristor. Together with the recent development of organic transistors, these findings bring about new research activities of organic conductors.