The present invention includes novel heterocyclic materials for use as blue phosphorescent materials in OLED devices. The novel materials include two fused 5-membered aromatic or pseudoaromatic rings, which are bonded with 6 membered aromatic rings to serve as chelation ligands for a transition metal. The novel materials were determined computationally to have appropriate triplet energies for use as blue emitters and to possess sufficient chemical stability for use in devices.