Cationic dyes have a high cluster and weak lightfastness. These kinds of dyes work best with acrylic fibers and make deep dyeing and washing fastness. The best choice of dyes for dyeing acrylic fibers is cationic or better to say basic dyes. The terminal group in a macromolecule in polyacrylonitrile carries a negative charge which creates the advantage of dyeability with cationic dyes. The reason is that; In the process of dying a strong bond between fiber’s anion and cation dyes will be created which increases the washing fastness of acrylic fibers.