Bromocresol Green, a triphenylmethane dye, serves primarily as a pH indicator transitioning from yellow (λmax=435 nm, protonated form) at pH 4.15 to blue (λmax=615 nm, deprotonated form) in alkaline environments. Utilized in biochemical analysis, it quantifies serum protein and albumin, assesses creatinine concentration, and evaluates cell viability [1] [2] [3] [4]. The dye exhibits a bio-based, yellow-green to blue-green hue.