Used as a reagent in analytical chemistry for the detection and estimation of certain anions such as nitrate and nitrite due to its ability to form characteristic colored complexes. Also employed in educational laboratories to demonstrate coordination compounds and ligand substitution reactions. Its deep blue color makes it useful in qualitative experiments to illustrate complex ion formation. Additionally, it has been used in some textile dyeing processes as a mordant to help fix dyes on fabrics. Limited use in electroplating solutions where copper ions are required in a stabilized complex form.