Nine new cyclometalated platinum(II) complexes of the formula [PtCl(arylolefin)(Q)] (2, 3) and [Pt(arylolefin)(N,O)] (4–10) (arylolefinH: eugenoxyacetic acid, isopropyl eugenoxyacetate; Q: quinoline; (N,OH): quinolin-8-ol, 2-methylquinolin-8-ol, 5,7-dichloroquinloin-8-ol and quinoline-2-carboxylic acid] were synthesized and fully characterized by EA, ESI mass spectrometry, IR and NMR spectroscopy and single-crystal X-ray diffraction for 3, 7 and 10. The results show that the arylolefin binds with PtIIvia the C5 atom of the phenyl ring and the CC allyl in all the synthesized complexes. Quinoline coordinates with PtIIvia its N atom in 2, 3, while deprotonated (N,OH) coordinates with PtIIvia both the N and O atoms in 4–10. The N atom of Q and (N,O) in all complexes are at the cis position with respect to the allyl group of the arylolefin. The XRD confirms the square-planar coordination of PtII and trans position of the arylolefin and quinoline ligands. The results of in vitro cytotoxicity tests against human cancer cell lines KB and Lu of 2, 4–8 indicate that 4 and 5 exhibit the highest activities against Lu and KB cell lines with the IC50 values of 7.1 and 4.1 µM, respectively, which are approximately 6 and 4 times lower than cisplatin.