Diels-Alder reactions of benzylidenecyanomethyl-1, 3-benzothiazoles and -1, 3-benzoxazoles 2a-f as 1-aza-1, 3-butadienes are described. The dienes 2, featuring the stabilized imine moieties by constituting heteroaromatic rings, react with both electron-deficient and electron-rich dienophiles 3a-c to give corresponding cycloadducts 4-6, regioselectively. The cycloadditions of the intramolecular systems 8a-d smoothly undergo via exo-transition state, stereoselectively affording polycyclic compounds 9a-d in good to excellent yields.