new methylene blue new methylene blue new methylene blue (also nmb) is an organic compound of the thiazine class of heterocycles. it is used as a stain and as an antimicrobial agent. it is classified as an azine dye, and the chromophore is a cation, the anion is often unspecified. new methylene blue identifiers cas number 1934-16-3 y 3d model (jsmol) interactive image chemspider 16736255 y echa infocard 100.026.833 pubchem cid 73518 unii 5gcz112bcn y inchi inchi=1s/c18h22n3s.clh/c1-5-19-13-9-17-15(7-11(13)3)21-16-8-12(4)14(20-6-2)10-18(16)22-17;/h7-10,19-20h,5-6h2,1-4h3;1h/q+1;/p-1 ykey: nzycyaskvwsana-uhfffaoysa-m yinchi=1/c18h22n3s.clh/c1-5-19-13-9-17-15(7-11(13)3)21-16-8-12(4)14(20-6-2)10-18(16)22-17;/h7-10,19-20h,5-6h2,1-4h3;1h/q+1;/p-1key: nzycyaskvwsana-rewhxwofar smiles .cc1cc2nc3cc(c)c(cc3c2cc1ncc)ncc properties chemical formula c18h22n3s:scl zncl2 molar mass 484.22 g/mol melting point 239 °c (462 °f; 512 k) boiling point decomposes except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). n verify (what is yn ?) infobox references applications nmb is a staining agent used in diagnostic cytopathology and histopathology, typically for staining immature red blood cells. it is a supravital stain. it is closely related to methylene blue, an older stain in wide use. safety new methylene blue is toxic. skin contact or inhalation should be avoided.