The multiple interaction between water, benzene, and hexafluorobenzene was discussed in light of an ab initio study. It was found that two trimers are formed with a dissociation energy of about 21 and 16 kJ/mol, which are greater than that of the benzene/water, hexafluorobenzene/water, and benzene/ hexafluorobenzene dimers. The lowest energy trimer features the two aromatic systems lying in tilted planes, with the water molecule interacting with benzene through one pi-hydrogen bond and with hexafluorobenzene through the oxygen atom. The highest energy trimer shows the aromatic systems lying in parallel planes and "sandwiching" water, which uses two hydrogens to bind benzene and the oxygen atom to interact with hexafluorobenzene.