Two dinuclear complexes namely [(UO2)2(L1)2(DMSO)2] (1) and [(UO2)2(L2)2(DMSO)2] (2) of two Schiff base ligands 2-[(2-hydroxy-3-methoxy-benzylidene)-amino]-2-hydroxymethyl propane-1,3-diol (HL1) and 2-[(3,5-dichloro-2-hydroxy-benzylidene)-amino]-2-hydroxymethyl-propane-1,3-diol (HL2) obtained by condensation of the aldehydes 2-hydroxy-3-methoxy-benzaldehyde and 3, 5-dichloro salicylaldehyde with tris(hydroxymethyl)aminomethane ammine, have been synthesized. On the other hand, when the two aldehydes were treated with uranyl nitrate two mononuclear complexes, [(UO2)(L3)2(DMSO)2] (3) and [(UO2)(L4)2(DMSO)2] (4), are obtained. The complexes are then heated at 800 °C in open atmosphere to obtain the U3O8 nanomaterials as the final product. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were employed to characterize the so obtained the U3O8 nanoparticles. Studies shows the synthesized U3O8 nanoparticles obtained from different complexes were different as far as morphology and size are concerned. All four different U3O8 nanoparticles explored as oxidising catalyst to oxidize alcohols where morphology of the nanoparticles controls the catalytic efficiency.