Late-stage functionalization is an important strategy to diversify complex natural products and approved drugs to potentially discover new uses. The approved drug clofibrate 1t has been used to bench-mark late-stage functionalization reactions at both the chloride leaving group and aromatic C-H bonds (Scheme 3). The chloride leaving group of clofibrate has been used to introduce a range of C-C as well as C-B and C-N bonds. The C-H bonds of clofibrate, especially the one ortho to the oxygen substituent, has been functionalized with C-N, C-F, C-D, C-C, and C-B bonds. In this work, we demonstrate the first example of aryne formation on clofibrate via the two-step thianthrenation and aryne formation/trapping sequence (Scheme 3). The overall yield for this process is 55% from clofibrate and the chloride and ester groups remain intact. Scheme 3. Formal dehydrogenation of clofibrate.