Used as a base and source of caesium in organic synthesis, particularly in coupling reactions such as the Sonogashira and Suzuki reactions. Enhances reactivity and solubility in palladium-catalyzed transformations. Employed in the preparation of pharmaceuticals, agrochemicals, and fine chemicals due to its ability to facilitate carbon-carbon bond formation. Also utilized in the production of specialty glasses and optical materials for its high refractive index and low melting properties. Plays a role in catalysis and material science, including the synthesis of nanomaterials and perovskites for solar cells.