A new class of solution processable dendrimers based on cyclic phosphazene (CP) cores have been prepared and used as host materials for blue and green organic light emitting diodes (OLEDs). The dendrimers are prepared in high yield from minimal step reactions, are soluble in common solvents for solution processing, are amorphous, and have excellent thermal properties necessary for application in OLEDs. OLED efficiencies of 10.3 cd/A (4.2 lm/W) and 35.3 cd/A (33.5 lm/W) were achieved using commercially available Flrpic and lr(mppy)(3) as blue and green phosphorescent emitters, respectively. These efficiencies were 2 x higher than control devices prepared using poly(N-vinylcarbazole), the most commonly used host material in solution processed phosphorescent OLEDs. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 531-539, 2011