The reaction of 3',5'-di-O-acetylthymidine with [Pt(PPh3)(4)] and KCl yielded a platinum(II) complex where the platinum is co-ordinated to the nucleobase through the N3 atom. In a similar reaction 1-methylthymine (1-MeThy) furnished the complex cis-[PtCl(1-MeThy)(PPh3)(2)], whose structure was determined by spectroscopic data and single crystal X-ray diffraction. When 1-MeThy was treated with [Pt(PPh3)(4)] in the absence of chloride ions the complex trans-[Pt(OH)(1-MeThy)(PPh3)(2)] was obtained.