In summary, we have developed a BF3• Et2O-catalyzed formal [2π + 2σ] cycloaddition of benzofuran-derived oxa(aza)dienes with bicyclo[1.1.0]butanes. A series of diverse meaningful spiro[benzofuran-2,2'-bicyclo[2.1.1]hexanes] were obtained in an efficient (up to 99% yield) and economical way. The reaction proceeds under mild conditions with high functional group tolerance and broad substrate scope. We anticipate that the synthesized benzofuran-fused spirocycles can be instrumental in the discovery of pharmaceutical molecules and further studies of construction of spirocycles by dipolar cycloaddition of bicyclo[1.1.0]butanes are currently underway in our laboratory.