Preparative oxidation of 1,3-diarypropynones ArC≡CCOAr in a system CF₃COOH-CH₂Cl_2-PbO₂ at 18-20°C within 1.5-25 h results in 1,1,2,2-tetraaroylethenes (ArCO)₂C= C(COAr)₂ in yields up to 75%. The most easily and efficiently the products form from the substrates where the aryl moiety conjugated with the triple bond contains electron-donating substituents p-MeO, p-Me, and p-t-Bu. On heating with hydrazine 1,1,2,2-tetrakis(4-methoxyphenylcarbonyl)ethene is converted into heterocyclic structures: pyridazine and 2,3,6,7-tetraazanaphthalene derivatives.