The electrochemical properties of thiacalix[4]arene (TCA) and p-tert-butylthiacalix[4]arene (BuTCA) in the presence of various metal ions were investigated by voltammetry, in organic and aqueous acetonitrile solution (pH 8). Their behavior were closely related to the complex formation by entrapping metal ions into the cavity of host molecules, and were compared with the results with calix[4]arenes. Thiacalix[4]arenes showed better binding ability towards transition metal ions than alkali or alkaline earth metal ions. (C) 2004 Elsevier Ltd. All rights reserved.