The 1:1 intermediate generated by the addition of alkyl(aryl) isocyanides to dimethylacetylenedicarboxylate is trapped by benzoyl chloride to yield functionalized 2,5-dihydro-1H-pyrroles. The presence of electron-withdrawing groups at the para position of benzoyl chloride leads to tetrasubstituted furans. The structures of these products were confirmed by single-crystal X-ray diffraction studies.