New Y(III) and La(III) complexes with 4-bpy (4,4 0 -bipyridine) and trichloro-or dibromoacetates with the formulae: Y(4-bpy) 2 (CCl 3 COO) 3 ÁH 2 O I, La(4-bpy) 1.5 (CCl 3 COO) 3 Á2H 2 O II, Y(4-bpy) 1.5 (CHBr 2 COO) 3 Á3H 2 O III, and La(4-bpy)(CHBr 2 COO) 3 ÁH 2 O IV were prepared and characterized by chemical, elemental analysis, and IR spectroscopy. Conductivity studies (in methanol, dimethyloformamide, and dimethylsulfoxide) were also described. They are small, crystalline substances. The way of metalligand coordination was discussed. The thermal properties of complexes in the solid state were studied by TG-DTG techniques under dynamic flowing air atmosphere. TG-FTIR system was used to analyze principal volatile thermal decomposition and fragmentation products evolved during pyrolysis in dynamic flowing argon atmosphere for La(III) compounds.