Tris(quinolate)Al-III (Alq(3))-based metallocomplexes with electron-deficient or electron-rich aryl substituents display remarkable blue-to-red tuning of both photo- and electroluminescence, nescence, covering most of the visible-light region (see Figure). correlation between the electronic properties of the aryl substituents, highest occupied-lowest unoccupied molecular orbital (HOMO-LUMO) gap, and the emissive properties of the complexes suggests this approach may be used to design new light-emitting materials.