3,3'-[5',5''-Bis[3-(4-pyridinyl)phenyl][1,1':3',1'':3'',1'''-quaterphenyl]-3,3'''-diyl]bispyridine

BP4mPy, namely 3,3',5,5'-Tetra[(m-pyridyl)-phen-3-yl]biphenyl, is one of the most popular electron-transporting and hole-blocking layer materials used in OLEDs. It is electron deficient due to the electron-withdrawing nature of its four pyridine pendants. Together with electron-donating materials (e.g. TCTA), BP4mPy can also be used as an exciplex host for red, green, and blue phosphorescent OLEDs. BP4mPy aids effective energy transfer from exciplexes to emitters, thus leading to high efficiencies.