A convenient microwave-assisted protocol for the synthesis of hydroxyl-containing isoquinolines from a metal-free radical cyclization reaction of vinyl isonitriles with alcohols was developed with moderate-to-excellent yields. Vinyl isonitriles are coupled with alkyl radicals through direct catalytic functionalization of the α sp³ C–H bond of alcohols. The methodology demonstrates a broad substrate scope, shows excellent functional group tolerance, is highly atom-economical and highly efficient, thus enabling the preparation of diverse potentially valuable hydroxyl-containing isoquinolines.