New tri-functional ligands of the type R 2 NCOCH 2 SCH 2 CONR 2 (where R=iso-propyl, n-butyl or iso-butyl) were prepared and characterized. The coordination chemistry of these ligands with uranyl and lanthanum(III) nitrates was studied by using the IR, 1 HNMR and elemental analysis methods. Structures for the compounds [UO 2 (NO 3 ) 2 ( i Pr 2 NCOCH 2 SCH 2 CON i Pr 2 )] [UO 2 (NO 3 ) 2 ( i Bu 2 NCOCH 2 SCH 2 CON i Bu 2 )], [La(NO 3 ) 3 ( i Pr 2 NCOCH 2 SCH 2 CON i Pr 2 ) 2 ] and [La(NO 3 ) 3 ( i Bu 2 NCOCH 2 SCH 2 CON i Bu 2 ) 2 ] were determined by single crystal X-ray diffraction. These structures show that the ligand acts as a bidentate chelating ligand and bonds through both the carbamoyl groups to the uranyl and lanthanum(III) nitrate groups. Solvent extraction studies show that the ligand can extract the uranyl ion from the nitric acid medium but does not show any ability to extract the americium (III) ion.