A simple monomeric tungstate, TBA2 [WO4](I, TBA= tetra-n-butylammonium), could act as an efficient homogeneous catalyst for chemical fixation of CO2 with 2-aminobenzonitriles to quinazoline-2, 4 (1 H, 3 H)-diones. Various kinds of structurally diverse 2-aminobenzonitriles could be converted into the corresponding quinazoline-2, 4 (1 H, 3 H)-diones in high yields at atmospheric pressure of CO2. Kinetics and DFT calculations showed that I plays an ...