The carboxylate ligand-exchange reaction of copper(l) trifluoroacetate by 3,5-difluorobenzoate yielded a new product, [Cu(O2C(3,5-F)(2)C6H3)] (1). Single crystals of 1 suitable for X-ray structural characterization were obtained by sublimation-deposition procedures at 230 degrees C. An X-ray diffraction study revealed a remarkable planar hexanuclear copper(I) core supported by bridging carboxylates, the first such structural type among other known copper(I) carboxylates. The Cu center dot center dot center dot Cu distances within the core range from 2.7064(8) to 2.8259(8) angstrom and fall into the category of cuprophillic interactions. The hexacopper unit remains intact upon gas-phase deposition with a planar polyarene, coronene (C24H12), to give [Cu-6(O2C(3,5-F)(2)C6H3)(6)](C24H12) (2). Density functional theory calculations suggest the latter compound to be a cocrystallization product having electrostatic interactions between the hexacopper complex and coronene. However, cocrystallization affects the photophysical properties of 2. While copper(l) 3,5-difluorobenzoate (1) exhibits photoluminescence at ca. 554 nm (lambda(ex) = 350 nm) in the solid state, compound 2 is nonluminescent at room temperature in the visible region. Gas-phase and solution reactions of 1 with alkyne ligands, diphenylacetylene (C14H10) and 1,4-bis(p-tolylethynyl)benzene (C24H18), result in the rupture of the [Cu-6] core to afford dinuclear organometallic copper(l) complexes. The latter have a dimetal core cis-bridged by two carboxylate groups with acetylene ligands eta(2)-coordinated to each copper(l) center.