Selenoindirubins and selenoindirubin-N-glycosides were prepared by the reaction of isatins and isatin-N-glycosides with 3-acetoxy-benzo[b]selenophene, respectively. While selenoindirubin-N-glycosides have not been reported before, three non-glycosylated selenoindirubins were previously reported, but without quantities, yields, scales, experimental details and spectroscopic data. In addition, the work could, in our hands, not be reproduced to prepare pure products. The present paper includes an optimized procedure for the synthesis of selenoindirubins and their complete characterization. Both selenoindirubins and selenoindirubin-N-glycosides showed antiproliferative activity in lung cancer cell lines. In melanoma cells, antiproliferative effects were further accompanied by induced apoptosis in combination with the death ligand TRAIL.