A luminescent material including a compound of the formula: ##STR1## where: n is an integer of 2 or 3; M is a divalent metal or a trivalent metal; G is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, both the aryl and the heteroaryl groups having 6 to 24 carbon atoms, wherein the substituted aryl or heteroaryl group is an alkyl, haloalkyl group having 1-8 carbon atoms, an alkoxy or haloalkoxy group having 1-18 carbon atoms, halogen, cyano, amino, amido, sulfonyl, carbonyl, aryl, or heteroaryl; and R.sup.1 and R.sup.2 are individually hydrogen, an alkyl or haloalkyl group having 1-18 carbon atoms, halogen, cyano, amono, amido, sulfonyl, carbonyl, and 5-24 atoms necessary to complete a fused aromatic ring.