The synthesis and spectroscopic characterization (infrared, 1 H, 13 C, 119 Sn NMR and 119 Sn M össbauer) of three organotin derivatives incorporating carboxylate ligands, with general formulae (C 6 H 11 ) 2 CHCOOSnPh 3 (1), (CH 3 NH)C 6 H 4 COOSnPh 3 (2) and 3,5-(NO 2 ) 2 C 6 H 4 CO 2 SnMe 3 (3) are reported together with their X-ray crystal structures. The compounds were obtained by the condensation, in ethanol, of the appropriate carboxylic acid with triphenyltin hydroxyde (1, 2) or trimethyltin hydroxide (3). In the case of triphenyltin(IV) derivatives, 1 and 2, the values of the M össbauer quadrupole splitting and the infrared data [ ν = (ν as (O-C O) -ν s (O-C O)) > 230 cm -1 ] are consistent with the presence of monomeric species in the solid state. X-ray crystallographic analysis confirms their structures as consisting of monomeric species, featuring distorted tetrahedral environments around the tin atoms. In both structures, one CSnC angle is relatively opened compared with the two others, which may be linked to the relatively close approach of the non-bonding oxygen of the carboxylate ligand to the tin center (Sn(1)-O(2) = 2.659(1) Å and 2.773(1) Å in 1 and 2 respectively). NMR data show the presence of monomeric species in solution, as found in the solid state. A significant intramolecular hydrogen bond is noticed between the hydrogen atom of the N-methylanthranilate ion and the non-coordinating oxygen atom in 2 (H(1A)-O(2) = 2.06 Å, N(1)-H(1A)-O(2) = 132 • ). Infrared and M össbauer spectroscopy and X-ray diffraction have shown that 3 has an infinite chain structure in which the central tin atom adopts a distorted trigonal bipyramidal coordination with two oxygen atoms in axial positions, the three carbon atoms of the methyl group occupying equatorial sites. The 3,5-dinitrobenzoate anions act as bidentate bridging ligands and the SnC 3 moieties are asymmetrically trans-coordinated (Sn-O(1) and Sn-O(2): 2.181(1) and 2.501(2)). 13 C and 119 Sn NMR data reveal a cleavage of the infinite chain structure of 3 in solution; the 119 Sn chemical shift value (124.0 ppm), in conjunction with the magnitude of the coupling constant [ 2 J( 119 Sn-C-H) = 58.8 Hz; 1 J( 119 Sn-C) = 393.6Hz], is consistent with a tetrahedral environment around the tin center.