New Pt(ii) and Pd(ii) complexes with the metal center coordinated to two different chelating ligands, tropolone (trop) and dihexadecyl-2,2'-bipyridine-4,4'-dicarboxylate bipyridine (bipy), [(bipy)M(trop)][CF(3)SO(3)], have been synthesized and their biological evaluation has been performed demonstrating a remarkable cytotoxic activity in vitro against the human prostate DU145 and hormone-sensitive LNCaP cells lines. Moreover, for the Pt(ii) derivative, the molecular structure has been determined by single-crystal X-ray diffraction and computational analysis on the hydrolysis reaction mechanisms have been performed by density functional theory (DFT) calculations, in order to correlate molecular structure, biological activity and mechanism of action of this new class of complexes based on two different bioactive fragments.