A metal‐free 2+2 cycloaddition and 1,4‐addition sequence induced by S‐centered radicals has been achieved by treating benzene‐linked allene‐ynes with aryldiazonium tetrafluoroborates and DABCO‐bis(sulfur dioxide) in a one‐pot procedure. The reaction provides a greener and more practical access to functionalized cyclobutaanaphthalen‐4‐ols with valuable applications. More than 50 examples are demonstrated with excellent diastereoselectivity and chemical yields. The reaction pathway is proposed to proceed by the following steps:2+2 cycloaddition, insertion of SO2, 1,4‐addition, diazotization, and tautomerization. Just a DAB: A new metal‐free 2+2 cycloaddition/S‐centered radical induced 1,4‐addition sequence of benzene‐linked allene‐ynes has been established by treatment with aryldiazonium tetrafluoroborates and DABCO‐bis(sulfur dioxide) under convenient reaction conditions, thus providing practical access to functionalized cyclobutaanaphthalen‐4‐ols of chemical and biomedical importance. DABCO=1,4‐diazabicyclo2.2.2octane.