Bromocresol green (BCG) is a dye of the triphenylmethane family (triarylmethane dyes). It belongs to a class of dyes called sulfonephthaleins. It is used as a pH indicator in applications such as growth mediums for microorganisms and titrations. In clinical practise, it is commonly used as a diagnostic technique. The most common use of Bromocresol green is to measure serum albumin concentration within mammalian blood samples in possible cases of renal failure and liver disease.

Function:
1. Used as an acid-base indicator with a pH change range of 3.8 (yellow) to 5.4 (blue-green). The sodium salt aqueous solution is used for spectrophotometric determination of the enthalpy of the developer.
2. As a reagent for the determination of aliphatic hydroxy acids and alkaloids by thin layer chromatography and an extractive separating agent for the determination of quaternary ammonium cations by photometry.