Thin derivatives of thiacalix[4]arene film were deposited using the technique of thermal evaporation under vacuum to fabricate a copper chemical sensor. Impedance sepectroscopy measurements were made to study the sensitivity and selectivity of thiacalix[4]arene (TCA[4H])-and p-tert-butyl thiacalix[4]arene (TCA[4+])-based sensors towards copper metal ions. The TCA[4H]/gold electrode device has shown a better limit of detection (10(-8) M) and larger linear range (over three decades) of copper activity compared to the TCA[4+]/Au-based sensors. (c) 2005 Elsevier B.V. All rights reserved.