Organic-inorganic hybrid materials of the type MeQ(diamine)1/2 (where Me–Zn, Cd, Mn and Q–S, Se, Te) belong to the class of 3D nanomaterials. They are built of layers of II–VI semiconductors and amines, which act as linkers. The main goal of our work was the synthesis of compounds of the type ZnxCd1-xSe(1,3-diaminopropane)1/2 and ZnSySe1-y(1,3-diaminopropane)1/2 (where x, y = 0, 0.25, 0.5, 0.75, 1) and the study of properties changed by the composition of the semiconducting layers. Analysis of these materials was carried out with the use of X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC) as well as temperature dependent XRPD enabled us to obtain information about the thermal stability of hybrid compounds with mixed semiconducting layers. Another important part of our work was a study, performed with the use of UV–vis spectroscopy, of the optical properties of these materials.