Mild conditions have been developed to achieve Pd-catalyzed homocoupling of indoles with excellent regioselectivity in the presence of Cu (OAc) 2· H2O in DMSO at room temperature in high efficiency. This method provides a simple route to 2, 3′-biindolyls from the electron- rich to moderately electron-poor indoles. The reaction tolerates the bromide substituent on indoles. In addition, a one-pot approach to C3-position acetoxylated biindolyls is realized ...