The aim of this proposal is to use synchrotron radiation to solve by temperature-dependent powder XRD (TD-PXRD), total scattering analysis (PDF) and EXAFS the structure of hybrid organic-inorganic materials formulated (CnH2n+1-NH3)2MIICl4 (n = 6, 12, 13; M = Mn, Cu, Zn). The thermally-induced phase transitions are associated with strong reorganizations of the aliphatic chains, dynamic disorder and present high enthalpies of transformation. For this reason, this family of materials is promising for thermal energy storage applications.