The crystal and molecular structures of the aryldiazenato complexes of molybdenum, [Mo(N₂C₆H₅)(S₂CNMe₂)₃],CH₂Cl₂ (1), and the m-nitro derivative [Mo{N₂C₆H₄(m-NO₂)}-(S₂CNMe₂)₃]₂,½CH₂Cl₂,½H₂O (2), have been determined by single-crystal X-ray diffraction methods at 294 K. Crystals of (1) are monoclinic, P2₁/n, a 13.056(1), b 13.366(1), c 15.350(1) Ǻ, β 93.80(1)°, Z 4. Crystals of (2) are monoclinic, C2/c, a 32.442(8), b 17.670(4), c 17.867(3) Ǻ, β 99.03(1)°, Z 8. Automatic diffractometry has provided significant Bragg intensities for 2849 (1) and 3898 (2) independent reflections and the structures have been refined by least-squares methods to R 0.036 (1) and 0.053 (2). The two unique molybdenum complexes in (2) are essentially chemically equivalent. The complexes in (1) and (2) possess the expected seven-coordinate pentagonal bipyramidal structures with the aryldiazenato ligands, singly bent, occupying axial positions. The N=N-Mo units are linear, and the bonding can be represented by N=N→Mo with the aryldiazenato ligands three-electron donors. The m-nitro substituent in (2) interacts with a dithiocarbamate (dtc) nitrogen atom, thereby affecting the redox behaviour of this compound. The possible significance of this O(nitro)...N(dtc) interaction to the mechanism, whereby included nitrobenzene solvent in the crystal lattice lowers the magnetic moments of ferric dithiocarbamates, is discussed.