The first heterobimetallic Bi:Sn alkoxide complexes [Bi2SnO(OCH(CF3)(2))(5)(O'Bu)(3)(THF)] (1) and [BiSnO(OCH(CF3)(2))(3)((OBu)-Bu-t)(2)](2) (2) are described. The complexes were obtained through mixing and heating equimolar quantities of the component alkwddes, Bi(OCH(CF3)(2))(3) and Sn(OtBu)(4), under solvent-free conditions (1) and in THF (2). The solid-state structures were determined by single crystal X-ray diffraction showing ligand redistribution from Bi(ITI) to Sn(IV) in the two molecular species. Compound 2 behaves as a single-source precursor for the thermolytic formation of bismuth pyrostannate, Bi2Sn2O7.