The effect of charge carrier mobilities on EL performances in electroluminescent diodes were discussed. It is stressed that quantum EL efficiency is no direct relation with charge mobilities but power efficiency may concern with charge carrier transport processes, because power efficiency is inversely proportional to drive voltage. Hole and electron mobility data on both bulk films and polymer-dispersed films were summarized and some discussions on the relation between molecular structures and charge mobilities were added. In addition, the meaning of designing high mobility materials for EL diodes is discussed. Our recent studies on the introduction of molecular alignment by use of liquid crystalline textures for the increase of charge mobilities were mentioned.