This review summarizes the research of bacterially produced dialkylresorcinols (DARs). We will give an overview about the DAR-related research during the last 40 years. Furthermore, a brief introduction into the class of ketosynthases (KS) and examples of these enzymes which show a deviation to the usual catalytic activity is given. One of these is DarB, which is involved in the DAR biosynthesis. The clustering and distribution of the DAR biosynthesis gene clusters (BGC), that has been identified in more than 100 genomes from taxonomically distinct bacteria, is discussed regarding the structures of the biosynthetic products from these BGCs. Finally, the biological activities of described DARs are summarized and possible methods for the detection and structure elucidation of DARs are given.