Eight diorganotin(IV)-oxo-carboxylates {[R2Sn(O(O)CR′)]2O}2 · Y (R′ = C4H3N2Y = H2OR = nBu 1, Y = 0 R = Me 2, Y = 0 R = C6H53, Y = 0 R = C6H5CH24; R′ = CH2SC4H3N2-2,6Y = 0 R = nBu 5, Y = CH2Cl2R = Me 6, Y = 0 R = C6H57, Y = 0 R = C6H5CH28) have been prepared in 1 : 1 molar ratios by reactions of diorganotin(IV) oxide with 2-pyrazinecarboxylic acid or (2-pyrimidylthio)acetic acid, respectively. All the complexes are characterized by elemental analysis, IR, 1H NMR and 13C NMR spectra. Except for 2, 4 and 7, the complexes are also characterized by X-ray crystallography diffraction analyses, which reveal that the complexes adopt the familiar dicarboxylato tetraorganodistannoxane structural mode. Among them, the evident difference is that weak intramolecular interactions between Sn and N atoms are recognized in complexes 1 and 3. However, for complex 5 two different coordination modes are found in the same lattice. [ABSTRACT FROM AUTHOR]