Two uranyl complexes having the composition [UO2(L)DMSO] were synthesized using salicyl- and 3,5-dichlorosalicylaldehyde-S-propyl-thiosemicarbazones as starting materials. The S-propyl-thiosemicarbazidato structures in the complexes are N-1-3,5-dichlorosalicylidene-N-4-salicylidene and N-1-salicylidene-N-4-3,5-dichlorosalicylidene. The stable solid complexes were characterized by means of elemental analysis, IR and H-1 NMR spectroscopies, and the single crystal X-ray diffraction technique. The two complexes, with the same formula, crystallize in different space groups. In the title complexes, the uranium atom is seven-coordinated in a distorted pentagonal-bipyramidal geometry involving an ONNO donor set of the thiosemicarbazidato ligand and an oxygen atom of a DMSO molecule. The two apical positions of the pentagonal bipyramid are occupied by the two oxygen atoms of the trans-dioxouranium group. The relative orientations of the DMSO and S-propyl groups in both complexes are somewhat different due to different crystal packing. (C) 2010 Elsevier Ltd. All rights reserved.