Luminescent metal complexes with organic ligand have been studied due to their potential applications as emissive layers in the organic light emitting devices. One of the typical examples is lanthanide complex. Lanthanide complexes are of great interest as they offer in combination of high luminescence efficiencies with narrow emission spectra. In this work we reported the characterization of a single layer organic light-emitting devices (OLED) which uses lanthanide complexes of Europium [Eu(EO4)(Pic)2(OH 2)]+(Pic)-.0.75(H2O) and Samarium [Sm(EO4)(Pic)2(OH2)]+(Pic)-.0. 75(H2O) as the emitting and electron transport layer. The lanthanide complexes have been synthesized by Saleh et al. The emission layer was deposited on the ITO substrate by spin coating technique with acetone as the solvent. The aluminium (Al) electrodes were thermally evaporated with at 1.0 x 10-5 mbar. UV-Vis absorption and photoluminescence (PL) spectra of the devices are also investigated. The PL spectra of Eu(III) exhibit sharp emissive peaks at 612nm with high intensity in comparison to that of Sm (III) complex at 581nm. From the UV-Vis absorption data clearly show the excitation of ligand band in the ultraviolet region that is associated to the complexes. The turn-on voltage of the OLED devices with Sm(III) was found to be higher than Eu(III) as clearly shown from their currentvoltage characteristics.