Abstract Aluminum and zinc complexes of 4-substituted 8-hydroxyquinoline were used effectively as emissive materials in light-emitting diodes (LED). The substituents chosen in this study were p-methoxy-2-styryl, p-diethylamino-2-styryl, and naphthalene-2-vinyl groups. Their emission spectra were red-shifted with respect to that of aluminum tris (hydroxylquinolate)(Alq 3) as a result of extending their π-conjugation. All complexes ...