2-Cyanobenzofurans and 2-cyanobenzothiophenes were prepared through an efficient one-pot Ullmann-reaction/cyanation reaction. In the presence of CuI/Na₂CO₃–Pd(OAc)₂/PPh₃ in DMF, the reaction of 2-(gem-dibromovinyl)phenols and 2-(gem-dibromovinyl)thiophenols with K₄Fe(CN)₆, as non-toxic and user-friendly cyanating reagent, proceeded smoothly to generate the corresponding 2-cyanobenzofurans and 2-cyanobenzothiophenes in good yields.