The interface between aluminum and electroluminescent sexiphenyl (6P) is investigated by means of photoelectron spectroscopy together with quantum mechanical calculations. X-ray and ultraviolet photoelectron spectroscopy are used to reveal that the interaction of aluminum-often used as the electron-injecting electrode in light-emitting diodes-on a 6P surface is of the van der Waals type, i.e., the metal atoms physisorb on the organic compound. In addition, it is calculated that bond formation between Al atoms and phenylene oligomers is not energetically favored.