Used as a catalyst in organic synthesis, particularly in oxidation and coupling reactions. Commonly applied in electroplating processes to deposit copper coatings on metals and other conductive surfaces. Employed in the production of other copper compounds and pigments for ceramics and glass, imparting blue or green colors. Utilized in textile printing and dyeing as a mordant to fix dyes onto fabrics. Also serves in etching solutions for printed circuit boards and in analytical chemistry for detecting various substances through colorimetric methods.