Naphthol Green B is a coordination complex of iron that is used as a dye.
Naphthol Green B is the sodium salt of Naphthol Green Y (C.I. 10005).
The organic ligands each bind to iron as bidentate ligands through the nitrogen and the anionic phenoxide groups.
Naphthol Green B, also known as Acid Green 1, is a green nitroso dye used to stain collagen in histology and for polychrome stains with animal tissue.