Dithianes are versatile umpolung intermediates in organic synthesis but have rarely been employed in radical cross-coupling reactions. Here we describe the oxidative coupling method for alkyne difunctionalization under metal-catalyst-free conditions. The efficient protocol directly affords a variety of β-ketodithianes in good to excellent yields with high regioselectivities. It provides a general pathway for accessing valuable dithianes with controlled formation of a new C-C bond and a C-O bond via a radical coupling pathway.