The solid state −13C-NMR of captopril and its zinc complex were determined by using combined techniques of cross polarization, high-power decoupling and magic-angle spinning. It was shown that the conformation of captopril in solution and solid state are nearly similar as indicated by the NMR studies. However, it was concluded that the captopril-zinc complex has K2ZnL2planartrans-structure (L=Ligand=captopril). This was confirmed also by determining the amount of potassium in the complex through titration with sodium tetraphenylborate.