The reactions of trans-[PtX2(pic)2] (pic = γ-picoline, X = Cl−, NO3
−) with N-acetyl-l-cysteine (acSH) and glutathione (GSH) were monitored and followed by 1H and 195Pt NMR. In the reaction of trans-[Pt(pic)2(D2O)2](NO3)2 with acSH, in the 195Pt NMR spectra, the most intense peak observed was trans-[Pt(pic)2(acS)}2(µ-acS)]+ (3). The intermediate product which was not clearly seen in the spectra was formulated as trans-[Pt (pic)2(acS)(D2O)]+ (2), with the weaker peak one as trans-[Pt(pic)2(acS)2] (1). With GSH, the main product observed was trans-[Pt(pic)2(GS)2] (4), while the intermediate product was not observed during this study. In the reactions of trans-[PtCl2(pic)2] with acSH, besides complexes 1 and 3 formed, the formation of trans-[Pt(pic)2Cl(acS)] (6) was also observed in the NMR spectra, while when it was reacted with GSH, followed a similar course to that of with acSH, but more slowly.