Thymol blue sodium salt is widely used as a pH indicator in various analytical applications. It is particularly effective in titrations to determine the acidity or alkalinity of a solution, transitioning from red to yellow in acidic conditions (pH 1.2–2.8) and from yellow to blue in alkaline conditions (pH 8.0–9.6). This makes it valuable in laboratory settings for monitoring pH changes during chemical reactions. It is also employed in microbiology for preparing culture media to ensure optimal pH conditions for microbial growth. Additionally, it is used in educational demonstrations to visually illustrate pH concepts in chemistry classes. Its stability and clear color transitions make it a reliable tool for both research and teaching purposes.