A dichloro Pt(II) complex with N-heterocyclic amine cis-Pt(PIEAM)Cl2, C-1 (where PIEAM = 1-(2-aminoethyl)piperidine) was synthesized and hydrolyzed to the corresponding [Pt(PIEAM)(OH2)2]2+ C-2 to explore its bioactivity and cytotoxic property. Biorelevant sulfur-containing small tripeptide glutathione (GSH)- and amino acid dl-methionine (dl-meth)-substituted complexes [Pt(PIEAM)(GSH)] C-3 and [Pt(PIEAM)(dl-meth)]+2 C-4 were synthesized and characterized. In vitro pharmacokinetic reactions of complex C-2 → C-3 and C-4 with GSH and dl-meth, respectively, were studied under pseudo-first-order reaction conditions. The high and negative entropy of activation (ΔS†) and low and positive enthalpy of activation (ΔH†) values were deduced from the Eyring equation to propose an associative mechanism. To find out the biotransformation of complex C-1, C-2, and Pt(II)-S chelates C-3 and C-4 to Pt(II)-DNA adducts, DNA binding affinity of C-1-C-4 was examined by UV-visible spectroscopy, fluorescence quenching, and gel electrophoresis methods. BSA binding activity of these complexes was emphasized for their biological importance and the "drug reservoir"activity. Anticancer activity of these complexes on HEp 2 (laryngeal), MDA-MB-231 (breast), and A549 (lung) cancer cell lines was found to be remarkable as compared to the recognized anticancer drugs such as cisplatin, carboplatin, and oxaliplatin. Cell cycle arrest was also explored on HEp 2 cells of the complexes at a concentration corresponding to IC50 value and displayed significant cell death at the sub-G1 phase. © 2021 American Chemical Society.