Pararosaniline base is widely used in the field of histology as a biological stain. It is particularly effective in staining cell nuclei, allowing for clear visualization under a microscope. This property makes it valuable in medical diagnostics and research for identifying cellular structures and abnormalities. In addition to its role in staining, pararosaniline base is utilized in the manufacturing of dyes and inks. Its ability to produce vibrant colors makes it suitable for applications in textiles, paper, and other materials requiring high-quality colorants. The chemical also finds use in analytical chemistry as a reagent for detecting specific substances. For instance, it is employed in tests to identify aldehydes and sulfites, aiding in various laboratory analyses. Furthermore, pararosaniline base has been explored in environmental science for monitoring air quality. It is used in methods to measure formaldehyde levels, helping to assess pollution and ensure safety in industrial and residential settings.