Martius yellow-Acid yellow 24

Martius yellow is a compound with formula C₁₀H₆N₂O₅. It is a dye.

Martius yellow stains have been used to stain erythrocytes yellow so that they contrast well with red fibrin in trichrome staining methods such as Lendrum’s Picro Mallory and Slidder’s Martius, Scarlet and Blue (MSB). It can be combined with other small molecular weight yellow dyes to increase stain intensity.