Indigo+dye

Name: (2E)-2-(3-Oxo-1,3-dihydro-2H-indol-2-ylidene)-1,2-dihydro-3H-indol-3-one Formula:C16H10N2O2 Molar Mass: 262.27 g/mol Melting Point: 734°F (390°C) Boiling Point:decomposes Density: 1.417g/cm 3

http://www.chemspider.com/Chemical-Structure.4477009.html