Mixed-ligand nitrile- and carbonyl-isocyanide complexes of platinum(II) trans-[PtCl₂(NCEt)CNXyl] and trans-[PtCl₂(CO)CNXyl] (Xyl = 2,6-Me₂C₆H₃) have been prepared for the first time. The compounds have been characterized by mass spectrometry, IR and NMR spectroscopy. Reactivity of the prepared complexes towards N-nucleophiles has been studied using the reaction with p-toluenesulfonyl hydrazide as the example.