Used as a pH indicator in laboratory and industrial applications, Neutral red changes color from red in acidic conditions to yellow in alkaline conditions in response to acidity or alkalinity, making it valuable in monitoring pH levels during experiments and processes. It is commonly employed in cell biology for viability assays, where live cells take up the dye and retain it in their lysosomes, indicating metabolic activity. Also used in microbiology for selective media to differentiate bacterial species based on their pH changes during fermentation. Its sharp color transition around pH 6.8 to 8.0 makes it suitable for titrations and environmental testing, such as water quality analysis. Additionally, it serves in histology as a staining agent for microscopic examination of tissues.