Thymolphthalein is widely used as a pH indicator in various laboratory and industrial applications. It is particularly useful in titrations to determine the endpoint of acid-base reactions, where it changes color in the pH range of 9.3 to 10.5, transitioning from colorless to blue. This property makes it valuable in analytical chemistry for assessing the alkalinity of solutions. Additionally, it is employed in educational settings to demonstrate pH changes in experiments. Its stability and distinct color change make it a reliable tool for precise pH measurements.