Perylene imide derivatives are well known organic pigments that exhibit a variety of shades in the solid state from red via maroon to black. These materials have attracted attention as photoconductors for photoreceptors as well as materials for optical disks. 4-Phenylethyl derivative (EPH) is a commercial black pigment. However, 4-pyridylethyl derivative (EPY) is found to exhibit both red and black colors, depending on the solvent used for recrystallization. The colors are differentiated by molecular conformation in the crystal lattice, and the red color corresponds to the cis form while the black one is characterized by the trans form. Additionally, the excitonic interaction along the molecular stack is found to play an important role in the determination of the shade in the solid state.