A simple, facile and one-pot route for preparing SnO₂ nanoclusters embedded on a mesoporous Sn(IV) organophosphonate (MSnP) framework is described. Reaction of SnCl₄·5H₂O with a flexible tris-phosphonic acid, mesityl-1,3,5-tris(methylenephosphonic acid), in the presence of a surfactant under hydrothermal conditions produced the desired nanocomposite, SnO₂@MSnP. Analytical, spectroscopic and microscopic studies establish that SnO₂@MSnP composite is comprised of SnO₂ nanoparticles of an average size of 5 nm evenly and abundantly dispersed over the MSnP framework. The mesoporous metal organophosphonate support significantly augments the catalytic efficacy and vapor sensitivity of SnO₂ nanoparticles. The catalytic efficiency of SnO₂@MSnP was tested for two acid-catalyzed reactions: deoximation reaction and esterification of fatty acids. SnO₂@MSnP exhibits remarkable sensitivity towards ammonia and acetone vapors at near room temperature and under open atmospheric conditions. The present method represents an important step towards preparation of mesoporous metal organophosphonate supported metal oxide nanoclusters and hence offers easy access to functional metal oxide based nanocomposites.