Natural products that are selectively toxic towards cancer cells have attracted significant interest among medicinal chemists due to their specificity.[1] In particular, indole-based alkaloids play a versatile role in imparting cytotoxicity to many naturally occurring anticancer agents.[2] Figure 1 shows examples of bis-(indole)-derived natural products. Recently, bis (indole) alkaloids isolated from marine organisms have emerged as a new class of indole- ...