The temperature dependence of space-charge-limited currents in polybenzo[c]thiophene (PBCT) films in a sandwich structure of aluminum/PBCT/indium–tin–oxide is presented. Free carrier space-charge-limited currents are identified and the free carrier mobility has been estimated to be ∼3×10-5 cm2 V-1 s-1. A trap of concentration ∼1.8×1017 cm-3 and energy ∼0.67 eV from the highest occupied molecular orbital level is estimated. The thickness dependence of the current, at constant voltage, is very close to that expected for a space-charge-limited mechanism. The Tauc band gap determined by optical spectrophotometry was found to be ∼1.34 eV. © 1998 American Institute of Physics.