The percyanated dodecaborate anion [B-12(CN)(12)](2-) was prepared by reacting [B12I12](2-) with CuCN in the presence of a palladium catalyst at elevated pressure and temperature in a microwave reactor. The fully cyanated cluster was isolated as a tetraethylammonium salt in yields of up to 39% and characterized by NMR and IR spectroscopy and mass spectrometry. The crystal structure of a copper complex of the percyanated anion, (CH3CN)(3)Cu[mu-B-12(CN)(12)]Cu(NCCH3)(3), was determined by single-crystal X-ray diffraction.