2-Phenyl-3-hydroxy-4(1H)-quinolinones can be considered as aza-analogues of flavones, compounds which are known for the wide-range of their biological activity. These quinolinones were studied as inhibitors of topoisomerase, gyrase and IMPDH. They were tested for anticancer activity in-vitro and were also shown to possess immunosuppressive properties. This review is the first summarizing the synthesis and activity of the mentioned quinolinones.