A series of iridium complexes with 2, 5-diaryl-[1, 3, 4]-oxadiazole ligands were synthesized and their electrochemical, photophysical, and electroluminescent (EL) properties studied. It was found that electron-withdrawing or donating substituents on the phenyl ring affected the emission maxima. Complex 3, iridium (III) bis (2, 5-bis-(2-hydroxyphenyl)-[1, 3, 4] oxadiazolato-C2′, N3)(acetyl acetonate), was characterized by single-crystal X-ray ...