“…When considering the antiproliferative potential of copper(II) complexes, special attention is given to Cu(II)–terpyridine systems. − The chelating ability of 2,2′:6′,2″-terpyridine (terpy) and its derivatives (R-terpy) enhances complex stability, and their molecular structures facilitate noncovalent interactions with DNA through the major groove, − π-stacking between the plane of the aromatic rings and DNA base pairs, − and electrostatic binding. − Moreover, many Cu(II)–terpyridine systems can generate reactive oxygen species (ROS), giving rise to damage in the cytoplasm, mitochondria, and DNA. ,,,− Importantly, a broad range of possible structural modifications for 2,2′:6′,2″-terpyridine provide opportunities to enhance the anticancer profile and reduce side effects of Cu-based anticancer agents. Substituents introduced into the terpy framework have been shown to control the electronic and structural features of the resulting Cu(II) complexes, and thus their cytotoxicity behavior. ,,,,,,,− Exemplarily, the five-coordinated Cu(II) complex [CuCl 2 (R-terpy)] with 1-methyl-1 H -pyrrol-2-yl-2,2′:6′,2″-terpyridine exhibiting a rare trigonal-bipyramidal geometry induced by the bulky 1-methyl-1 H -pyrrole substituent, demonstrated no cytotoxic activity in tumor HCT116, A2780, A549, and MCF7 cell lines .…”