Diorganotin(IV) complexes of the type [{R 2Sn(ONC(Me)py)} 2O] 2(R=Bu n ( 1), Pr n ( 2), Et ( 3) and Me ( 4)) have been synthesized by the condensation reaction of R 2SnO with 2-NC 5H 4(Me)CNOH ( 5) in 1:1 molar ratio in refluxing anhydrous benzene–toluene and characterized by elemental analyses and IR and NMR ( 1H, 13C and 119Sn) spectroscopy. Two sets of 119Sn chemical shifts are observed in the 119Sn-NMR spectra of all of these compounds indicating the presence of two types of environment around the tin atoms in solution. The crystal structures of 1, 3 and 5 have been established by single crystal X-ray diffraction. The bonding in 1 differs from that in 3 but in both structures two different environments around the tin atoms are evident with the geometry around each tin atom being that of a distorted trigonal bipyramid with alkyl groups at the equatorial positions. The structure of 5 consists of chains of molecules arising from intermolecular hydrogen bonding involving the nitrogen atom of the ring.