Tris(8-hydroxyquinolinato)aluminium is the chemical compound with the formula Al(C<sub>9</sub>H<sub>6</sub>NO)<sub>3</sub>. Widely abbreviated Alq<sub>3</sub>, it is a coordination complex wherein aluminium is bonded in a bidentate manner to the conjugate base of three 8-hydroxyquinoline ligands.
Both the meridional and facial isomers are known as well as several polymorphs (different crystalline forms).
The compound is prepared by the reaction of 8-hydroxyquinoline with aluminium(III) sources
The synthesis and precipitation are so efficient that this reaction is used in gravimetric analysis for aluminium.
Alq<sub>3</sub> is a common component of organic light-emitting diodes (OLEDs). Variations in the substituents on the quinoline rings affect its luminescence properties.