Аннотация:The spin state of the previously described iron(II) clathrochelate in two photopolymer compositionsfor 3D printing is studied for the first time by ultraviolet−visible (UV−Vis) spectroscopy. The photopolymercompositions are shown to favor the temperature-induced spin transition that becomes sharper than thatin solutions or in crystalline films of this complex. A possibility of preparing objects of complicated shape andinternal geometry using photopolymer 3D printing from the compositions containing compounds with spintransitions provides broad prospects for their use in devices of soft robotics, for example, as actuators.