Oxovanadium(iv) and dioxouranium(vi) complexes of Schiff bases (L and L) derived respectively from pyrazine-2-carboxylic acid hydrazide and pyrazine-2,3-dicarboxylic acid dihydrazide with salicylaldehyde have been prepared. The Schiff bases behave as terdentate 0 (enolic) N (azomethine) 0 (phenolic) donors in their fully deprotonated complexes; bidentate 0 (keto) N (azomethine) donors in the hydroxo complexes and bidentate 0 (enolic) N (azomethine) donor in the partially deprotonated complex, (UO2)(2)(acac)(2)(L'-2H).