Organic LED has been drawing strong attention from various fields as the energy-saving light source of the new generation for illumination or display devices. Particularly, OLED has been investigated globally as an energy-saving planar light source that can be utilized in various designs at lower cost. Research efforts at Yamagata University culminated in the successful development of white-light OLED panel for the first time in the world, which eventually primed the way to the likewise successful development of multi-photon emission-type OLED devices capable of providing high luminosity and long life at a level sufficient for practical applications. Latest research projects OLED presently intends to focus on include the development of OLED device of the next generation by the liquid coating process under atmospheric environment, which is expected to achieve drastic reduction in the process' energy requirement from that of the conventional vacuum deposition process carried out in the high-vacuum environment.