A salient feature of the described method for sequential geminal 1,1-diarylation is that the order in which arenes are appended to the starting a-bromoacid is critical. A simple, stepwise graphical user-guide is therefore presented to provide practitioners with general guidelines regarding the preferred cadence of arene installation (Figure ). In step 1, the desired geminal 1,1-diarylated four-membered ring should be retrosynthetically disconnected to the corresponding a-bromoacid and the two resulting (hetero)aryl halides are individually evaluated in step 2. In this step, the corresponding class of each (hetero)aryl halide is placed into one of three categories (Figure ): (A) Type I, including five-membered rings such as indoles, indazoles, and pyrroles, as well as electron-poor arenes which are suitable for the first coupling; (B) Type II, including substituted pyridines which are suitable for both couplings; and (C) Type III, including unsubstituted pyridines, pyrimidines, and electron-rich arenes which are appropriate for the second coupling.