A mild and efficient two-step synthesis of 3-substituted β-carbolinone derivatives from 3-substituted β-carboline in good yields is described. A possible reaction mechanism for the formation of the skeleton of β-carbolin-1-one is proposed. The structures of these compounds were established by IR, 1H-NMR, 13C-NMR, mass spectrometry and elemental analysis, as well as X-ray crystallographic analysis of 4-2 and 6-2.