1992 the first blue organic light emitting diode (OLED) based on Parahexaphenylene (PHP) was presented by the Institute of Solid State Physics at Graz University of Technology. From these days on astounding progress has been made and present diodes show a brightness of about 100 cd/m2 at 4 Volt and provide lifetime and power efficiency sufficient to be commercially attractive. In contrast with the case of crystalline semiconductors, the fabrication processes allow the possibility of making very high resolution matrix displays by patterning the bottom and top electrode into perpendicular stripes. The use of fluorescent, or color-changing, media (CCM) is a promising strategy for achieving brilliant colors. In this case the PHP-based, blue OLED is used for primary emission. Externally the light is converted to green or red by the CCM.