Used as a pH indicator in analytical chemistry, particularly in titrations and biological experiments. It changes color from yellow to blue over the pH range of 3.8 to 5.4, making it ideal for detecting weak acids and bases. Commonly used in microbiology for bacterial differentiation, such as in citrate utilization tests. Also applied in environmental testing to monitor pH changes in water samples and soil extracts. Its clear color transition makes it suitable for educational lab demonstrations involving acid-base reactions.