Abstract: A series of emitting materials used for organic EL based on tridentate ligands are characterized as Formula 1, Formula 2 and Formula 3, where: the group O-I-N is a bidentate ligand such as 8-hydroxyquinoline and 2-(o-hydroxyphenyl)-benzoxazole, II, III are unsubstituted or substituted aryl groups. The substituted groups can have 1-8 carbon atoms, halogen, cyano, amino, amido, sulfonyl, carbonyl, aryl, or heteroalkyl groups. The ligand including II and III is a tridentate ligand with three chelate atoms: two oxygen atoms and one nitrogen atom. The central metal atoms can be trivalent or tetravalent atoms such as Al, In, Ga, Tl, and Sn. These materials can be used as emitting materials or electronic transport materials in organic EL devices.