Tris(trimethylsilyl) Phosphite is used in the studies of bisphosphonic acids as effective inhibitor of glutamine synthetase, a promising approach for the discovery of novel drugs against tuberculosis. It also acts as a reagent in the preparation of substituted calix[4]arenes bearing one or two α-hydroxymethylphosphonic acid fragments at upper rim of macrocycle as inhibitors of glutathione S-transferase in vitro.