Owing to cisplatin have extensive side-effects which led the investigators to go for non-platinum metal complexes for anti-cancer drug discovery. Among these, further ruthenium(II) and iridium(III), all others retains high toxicity in normal cells in addition to the cancerous ones. In this review newly developed several Ru(II) arene complexes, cyclometalated Ru(II) complexes, Ir(III)-cp* complexes and cyclometalated Ir(III) complexes have been reported. Most of the cases molecules are selectively targeting to the cancer cells with respect to normal cell. The mechanistic pathway of apoptosis was also highlighted in briefly. © 2020 Elsevier B.V.