AbstractSlow reaction of TiCl4 with S4N4 in CH2Cl2/CCl4 produces a mixture of two crystalline dinuclear complexes of composition [TiCl4(S4N4)]2. Crystal data for the orange-yellow α-isomer: monoclinic, space group P21/n with a = 11.608(3) Å. b = 8.304(3) Å, c = 10.938(5) Å, β = 101.06(4)° and Z = 2. Crystal data for the red-brown β-isomer: monoclinic, space group P21/c with a = 11.220(2) Å, b = 13.868(2) Å, c = 14.839(4) Å, β = 106.18(2)° and Z = 4. Crystal structure analyses reveal that the S4N4 molecules in the α-form act as 1,3-N,N′-bonded bridging ligands and in the β-form as N-bonded monodentate ligands.