Organic light-emitting diodes (OLEDs) possess a number of advantages over conventional display devices, such as high brightness and contrast, high luminous efficiency, fast response time, wide viewing angle, low power consumption, and light weight. In addition, the new technologies offer the potential of low manufacturing cost. OLED displays can be fabricated on large area substrates (including flexible substrates) and offer a virtually unlimited choice of colors. The technological promise of these unique characteristics puts OLEDs at the forefront of research efforts of a number of government agencies, industries, and universities. Many major industrial electronics giants and many newcomers have invested heavily inOLEDresearch and development. As a result, a stream of new OLED products has reached the marketplace and a number of large-scale manufacturing facilities are under construction. Though the field is growing rapidly and its impact is both pervasive and far-reaching, major challenges still remain, especially the lack of highly efficient, stable organic light-emitting materials, the insufficient operational lifetimes of the devices, and technical hurdles in large-scale manufacturing yields of the OLED displays. Overcoming these drawbacks will require further multidisciplinary studies.