Used as a chromogenic reagent in analytical chemistry for the detection and spectrophotometric determination of metal ions, especially copper(II), nickel(II), and cobalt(II). It forms stable, colored complexes with these metals, allowing for sensitive measurement in environmental, biological, and industrial samples. The color change upon complexation makes it suitable for visual or instrumental analysis. Also applied in the development of test strips and sensors due to its distinct color response. The reagent is sensitive to pH changes and solvent conditions, requiring precise experimental control for reliable results.