Safranine

Safranine dye on silk sample after exposure to 85 Mlx-h
Credit: E. Hagan et al.

Description

A family of red azo dyes derived from phenazine. In 1878, Perkin converted Mauveine to parasafranine, and the bright red, un-mordanted dyes were sold under the name 'safranine' for textiles. Theb asic dyes will readily bond to fabrics and were primarily used cotton, wool, silk) and leather. However, they were light-sensitive and not used for very long. Currently, under the name of safranin, the dyes are used as biological stains for bacteria in a Gram's test.

• Safranine O = CI 50240; Basic Red 2
• Safranine T = CI 50240

Chemical structure

Synonyms and Related Terms

Basic Red 2; Safranine O; safranina (Esp.); CI 50240; Basic Red 2; safranin; saffranine; phenosafranine; dimethyl safranin

Risks

• Contact causes skin irritation and eye damage.
• Hazardous to aquatic life.
• ThermoFisher: SDS

Physical and Chemical Properties

• Soluble in water and alcohol.
• Slightly fluorescent
• When concentrated sulfuric acid is added to a safranine solution, it will change from red to violet to blue to green. Once green, water can be added to dilute the solution and the colors will change back in reverse order.
• Composition = C20H19N4Cl (mol. wt. = 350.85 g/mol)
• CAS = 477-73-6 (safranine O)

Resources and Citations

• E. Hagan, I. Castro-Soto, M. Breault, et al. The lightfastness of early synthetic organic dyes. Herit Sci 10, 50 (2022).
• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
• F. Crace-Calvert, Dyeing and Calico Printing, Palmer & Howe, London, 1876
• Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
• Colour Index International online at www.colour-index.org
• Wikipedia: Safranin Accessed Feb 2026