 Sulfide-based luminescent materials have been widely studied for various lighting applications such as flat panel displays, field emission displays, and powder electroluminescence for backlights. These materials can emit light across the visible spectrum when doped with certain elements, such as cerium and europium. Additionally, sulfide materials have recently gained popularity due to their ability to produce a broadband red emission from europium-doped binary alkaline earth sulfides, such as calcium sulfide and strontium sulfide. Rare earth-doped binary alkaline earth sulfides, such as thio-galates, thio-aluminates, and thio-silicates, have also shown promise as conversion phosphors in white-light emitting diodes, felides, while intrinsic colloidal quantum dots, such as lead sulfide and cadmium sulfide, have demonstrated size-dependent luminescence. This article was authored by Philippe F. Smet, Ewan Morales, Sieger Hens, and others.