The present study involves synthesis and characterization of amorphous M(IV) phosphates and tungstates [M(IV) = Zr, Ti and Sn] which are inorganic ion exchangers of the class of tetravalent metal acid (tma) salts. The presence of protons contained in the structural hydroxyl groups indicates good potential for application in solid acid catalysis. The catalytic activity of the materials abbreviated as ZAP, Tip, SnP, ZrW, TiW and SnW has been explored by synthesizing some monoesters and diesters. Good yields are obtained in the case of monoesters as compared to diesters. The results reveal the promising use of tma salts as solid acid catalysts.