Bromophenol blue is also used as a colour marker to monitor the process of agarose gel electrophoresis and polyacrylamide gel electrophoresis. Since bromophenol blue carries a slight negative charge at moderate pH, it will migrate in the same direction as DNA or protein in a gel.
Methyl Green is used commonly with bright-field microscopes to dye the chromatin of cells so that they are more easily viewed. A basic dye used as a chromatin stain, as a differential stain for RNA amd DNA, and as a tracking dye for DNA in electrophoresis.
Sudan black B (C26H24N4O) is a lysochrome (fat-soluble-dye) diazo dye used for staining of neutral triglycerides and lipids on frozen sections.