Used as a pH indicator in analytical chemistry, bromothymol blue is especially effective in detecting weak acids and bases. It is commonly employed in titrations where the pH transition range is near neutral, typically changing color between pH 6.0 (yellow) to 7.6 (blue). This makes it ideal for measuring substances like carbon dioxide in aqueous solutions, as CO₂ dissolves to form carbonic acid, causing a visible color shift. It is widely used in biology laboratories to demonstrate respiration and photosynthesis in aquatic environments. Also found in microbiological media to monitor pH changes during bacterial growth. Its clear visual transition supports educational experiments and field testing where precise pH meters may not be available.