The reaction of dialkyl 2-[(dialkoxyphosphoryl)ethynyl]-2-(arylamino)malonates with bases (СН3СООK, t -ВuOK) can serve as a method for preparing original diphosphonylated 2,3-dihydro-1 Н -pyrroles and 4-phosphonylated 1-azabuta-1,3-dienes. A probable scheme for the formation of the obtained new compounds is proposed.