In coordination chemistry, azo ligands are organic chemicals capable of selectively absorbing and reflecting light at wavelengths within the visible range of the electromagnetic spectrum. A pigment is a colored substance that has an affinity for the colored substance. The dye needs a liquid medium often to be able to transfer to the colored material, and it may need a color anchor to improve the color fastness in the dyed fibers. Color results from the pigment, or pigment, as a result of their absorption of certain wavelengths of light. Pigments , unlike dyes in general, dissolve in water and have no affinity for dyed materials. Azo ligands have weak electron bonding in the conjugated system so that incident light can stimulate these electrons and give them the energy needed to jump from one energy level to another, which means absorbing some wavelengths of incident light. What is important is that a mixture of the remaining wavelengths is reflected, giving color.