TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Materials: The first host is a compound of formula (I). The aromatic amine has highest occupied molecular orbitals (HOMO) level of - 5.4 plus minus 0.2 eV. It comprises N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD), 1,1-bis((di-4-tolylamino) phenyl)cyclohexane (TAPC), N,N'-bis(4-methylphenyl)-N,N'-bis(4-ethylphenyl)-(1,1'-(3,3'-dimethyl)biphenyl)-4,4'-diamine (ETPD), tetrakis-(3-methylphenyl)-N,N,N',N'-2,5-phenylenediamine (PDA), triphenylamine (TPA), bis(4-(N,N-diethylamino)-2-methylphenyl)(4-methylphenyl)methane (MPMP), N,N,N',N'-tetrakis(4-methylphenyl)-(1,1'- biphenyl)-4,4'-diamine (TTB), N,N'-bis(naphthalen-1-yl)-N,N'-bis-(phenyl)benzidine (NPB), 4,4',4"-tris(N-carbazolyl)triphenylamine (TCTA), 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP), 1,3-di-(9-carbazolyl)benzene(mCP), and 4,4',4"-tris((3-methylphenyl)phenylamino)triphenylamine (m-TDATA). The dopant is a phosphorescent material, preferably a cyclometalated complex of iridium.R1-R4=H or aryl, and greater than or equal to 2 of which are aryl, preferably naphthyl, naphthylphenyl, phenylnaphthyl, carbazolyl, carbazolylphenyl, triphenylamino, arylanthracenyl, and a group of formula (Ia).R5=D, alkyl, alkoxy, or aryl;a=0-4;b=0-5;m=0-6;andD=not defined. EXAMPLE - Combined portions of diketone (5.5 g) were suspended in 39 mL phosphoryl chloride (POCl3) and 5.4 g phosphorous pentachloride was added. This was degassed and refluxed under nitrogen for 8 hours. Excess POCl3 was removed by evaporation. Ice was added to decompose the remaining chlorides and the mixture was neutralized with ammonia. The brown precipitate was collected and dried under vacuum while the mother liquor was extracted with methylene chloride. All brown material was combined, evaporated to a brown gum and methanol added. After shaking and stirring, a pale yellow solid was isolated which recrystallized as off-white needles from trichloromethane and methanol (1:10). The product was dichlorobathophenanthroline compound.