Eosin B (Acid Red 91) serves as a versatile dye utilized across various domains. Commonly employed in biological experiments, it aids in observing and analyzing cell structures, tracking biomolecules, evaluating cell functions, distinguishing cell types, detecting biomolecules, investigating tissue pathology, and monitoring microorganisms. Its utility extends beyond basic scientific research to include clinical diagnostics and a broad spectrum of applications. Additionally, Eosin B is employed in traditional sectors like textile dyeing and emerging areas such as functional textile processing, food pigments, and dye-sensitized solar cells.