Various dialkyl azodicarboxylates are of importance in organic synthesis due to their interesting reactivity. So dialkyl azodicarboxylates was investigated for the dehydrogenation of 1,2,3,4-tetrahydroquinolines to quinolines which are common pharmacophores in numerous pharmaceuticals and bioactive compounds. It was revealed that less sterically hindered diethyl azodicarboxylate showed the fastest reaction rate. Among solvents screened, chloroform exhibited superior results to others. A variety of 1,2,3,4-tetrahydroquinolines underwent the present dehydrogenation to produce the corresponding quinolines in high to excellent yields. Diethyl hydrazodicarboxylate which is reduced species of diethyl azodicarboxylate was easily separated for recycle.