Rare earth chelates of Sm(III) (complex 1) and Eu(III) (complex 2) with beta-diketone ligand (2-thienyl)trifluoroacetylacetone (HTTA) and triphenylphosphine oxide (TPPO) were prepared from their nitrate salts. Single crystal X-ray diffraction, FTIR and thermo-gravimetric analyses were used in the characterization. Both photoluminescence (PL) and electroluminescence (EL) properties of complex 2 were studied. In both crystalline powder and film states, the PL spectra exhibit emission peaks typical of europium (III) with the most intense at 615 nm. Single layer EL devices based on complex 2 fabricated by evaporation show only weak emissions, while double layer devices with a hole transporting layer of N,N-bis(3-methylphenyl)-N,N,"-diphenyl-benzidine (TPD) exhibit enhanced intensity indicating better carrier injection balance.