Stacking between aryl and perfluoroaryl units is an important class of aromatic–aromatic interactions that has been studied extensively since Patrick and Prosser demonstrated in 1960 that a 1:1 mixture of benzene and hexafluorobenzene forms a solid complex that melts at 24ºC [1]. Crystallographic studies have shown that this molecular complex consists of face-to-face stacks of alternating benzene and hexafluorobenzene molecules. Similar stacking motifs have been revealed in a large number of 1:1 complexes of perfluorinated aromatic compounds with non-fluorinated arenes. As the binding energy between benzene and hexafluorobenzene is ca. 4 kcal/mol, this interaction has emerged as a very important synthon in supramolecular chemistry that has a utility comparable to that of many robust hydrogen-bonding synthons. For example up till now, the aryl–perfluoroaryl interactions have been used to design crystals suitable for solid-state photopolymerization and to stabilize liquid-crystalline phases. These interactions also seems to offer new possibilities for the modification of biologically important structures. We are particularly interested in employing aryl–perfluoroaryl interactions in the construction of supramolecular aggregates from hydrogen-bonded or halogen-bonded assemblies. Therefore we have turned our attention to simple fluorinated compounds such as pentafluorophenol, pentafluorobenzoic acid, pentafluorobenzamide, pentafluroiodobenzene and discovered their extraordinary ability to form crystalline molecular complexes with a large diversity of non-fluorinated aromatic substrates. In this presentation structural characterization and some properties of these crystalline complexes will be reported.