The high-temperature solid-state desolvation under an inert atmosphere was studied for two new polymorphic complexes of the same composition (bath) 2 Sm 2 (piv) 6 ·2EtOH (piv=(CH 3 ) 3 CCO 2 − , bath=4,7-diphenyl-1,10-phenanthroline), which differ in the structural functions of the bridging carboxylate anions. This resulted in the synthesis of new non-solvated pivalate (bath) 2 Sm 2 (piv) 6 . The complexes (bath) 2 Sm 2 (piv) 6 ·2EtOH (two polymorphic modifications) and (bath) 2 Sm 2 (piv) 6 were characterized by X-ray diffraction. The solid-state thermal decomposition of binuclear Sm(III) pivalates with heterocyclic chelating N-donors, such as 2,2′-bipyridyl (bpy), 1,10-phenanthroline (phen), and bath, was studied, the composition of the complexes in the gas phase was determined, and the magnetic and luminescent properties were analyzed.