In order to obtain a better anhydrous precursor for various applications in materials science and catalysis, thermal dehydration reactions of Y(TFA) 3 (H 2 O) 3 (TFA=trifluoroacetate) (A) were investigated. Thermal treatment of A at different temperatures under vacuum (5×10 −2 mm) for several hours failed to give totally anhydrous yttrium trifluoroacetate (as indicated by IR). Two different complexes, a partially dehydrated [Y(μ,η 1 :η 1 -TFA) 3 (THF)(H 2 O)] 1∞ ·THF (1) and a partially hydrolyzed [Y 4 (μ 3 -OH) 4 (μ,η 1 :η 1 -TFA) 6 (η 1 -TFA)(η 2 -TFA)(THF) 3 (DMSO)(H 2 O)]·6THF (2), were obtained with good and moderate yield, respectively, by crystallization of two different thermally treated batches of A from THF (or THF+DMSO) at room temperature. More efficient dehydration of A could be achieved at 200°C in a furnace, the obtained anhydrous yttrium tris-trifluoroacetate giving Y(TFA) 3 (THF) 2 (3) on crystallization from THF. All the products were characterized by elemental analyses, FT-IR and 1 H NMR spectroscopy as well as thermo-gravimetric analysis. In addition, single crystal X-ray structures are reported for 1 and 2, which show either a terminal (η 1 and η 2 ) or bridging (μ,η 1 :η 1 ) bonding behavior of the TFA ligand.