Used as a pH indicator in analytical chemistry, particularly in titrations and colorimetric assays. It changes color from yellow to blue as the pH increases, with a transition range between pH 3.8 and 5.4, making it suitable for detecting weak acids and bases. Commonly employed in biological and environmental testing to determine acidity in solutions. Also used in microbiology for bacterial differentiation in culture media, where pH changes indicate metabolic activity. Its clear visual shift makes it ideal for educational lab experiments involving acid-base reactions.