A new approach to the two-photon decays of pseudoscalar mesons is proposed. In the case of spontaneously broken chiral U(4)Q9U(4) symmetry, our theory reproduces the experimental data on '-72r almost completely under suitable parameters chosen consistently with the possible existence of heavy charmed bosons above (1.5--2.0)GeV. It tempts us to favor the fractionally charged quartet model with lepton-baryon symmetry, although. other alternatives, i.e., the quarkor three-triplet models, are not to be disproved within our approximations.