We present an ultrahigh vacuum scanning tunneling microscopy (UHV-STM) and scanning tunneling spectroscopy study of ex-situ self assembled supramolecular dyads, consisting of fulleropyrrolidines (PyC 2 C 60) axially ligated to zinc (II) tetraphenylporphyrin (ZnTPP), self organized by axial ligation to a 4-aminothiophenol (4-ATP), self assembled monolayer on gold (111). By highly diluting the PyC 2 C 60 solution, and subsequently annealing in vacuum, isolated dyads are obtained; these show both bias polarity-dependent apparent height in STM images, and highly rectifying behaviour in tunneling spectroscopy. First principles density functional theory calculations clarify the conformational and the electronic properties of the 4-ATP/ZnTPP/PyC 2 C 60 system. The rectifying behavior is explained using a model based on the Aviram-Ratner mechanism.* Work supported by the CNR-INFM, by a NSF US-Italy …