The magnetic hybrid material, based on the aquapentachloridoferrate (III), [FeCl5(H2O)]2- and on the dicystaminium cation H2Cys, is reported for the first time in this paper exhibiting an interesting thermochromic behaviour. It was prepared as orange single crystals, suitable for single crystal X-ray diffraction, with the chemical formula (C4H14N2S2)2[FeCl5(H2O)]Cl2*H2O (1). The characterization by X-ray diffraction was carried out at room temperature 296 K and at 120 K. The new derivative displays an asymmetric unit, formed by two H2Cys cations, one anionic complex [FeCl5(H2O)]2- and two Cl−, that ensure the electroneutrality, all trapped in the matrix with one water molecule. It crystallizes in the triclinic space group with the following unit cell parameter at 120 K and 296 K respectively: a = 10.7913(4) Å, b = 11.4145(5) Å, c = 11.4225(5) Å and α = 99.010(4) °, β = 102.529(4) °, γ = 90.466(3); a = 10.8747(4) Å, b = 11.4717(5) Å, c = 11.5483(4) Å and α = 98.907(3) °, β = 103.169(3) ° γ = 90.635(3). The compound was also characterized by IR spectroscopy and by DSC analysis and its magnetic behaviour was investigated.