Visible light-responsive photocatalytic chalcogenide materials have important applications. In this chapter, classifications of chalcogenide and fundamentals are discussed. Chalcogenide nanostructures have attracted great attention from researchers due to their narrow bandgap energy, visible light harvesting ability, and various applications including solar energy utilization, photocatalytic activity under visible light, visible light-assisted water splitting, and removal of hazardous pollutants. This chapter also covers different types of sulfide-, selenide-, and telluride-based chalcogenides such as SnS, CdS, GaS, GaSe, MoS2, MoS3, CdTe, etc. and some their selected applications.