Photoinduced dissociation of two Mo-CN bonds in [Mo(CN)(8)](4-) affords the octahedral complex anion [Mo(CN)(6)](2-). This hexacyanomolybdate(IV) ion is also obtainable from tetracyanooxomolybdate via a thermal substitutional synthetic route. The anion represents the missing link in the ligand-field photolysis of octacyanomolybdate(IV); it is characterized by means of single-crystal X-ray diffraction, thermogravimetric analysis, and magnetic susceptibility measurements as well as IR, Raman, H-1 and C-13 NMR, and electronic spectroscopy.