Organic field-effect transistors were fabricated using N,N'-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13H27) as the active material and a polymeric insulator polymethylmethacrylate (PMMA) as the gate dielectric. A mobility value of 1.7 x 10(-2) cm(2) V-1 s(-1) was estimated from the transistor characteristics. The threshold voltage was 0.2 V and the inverse subthreshold slope was 7.6 V/decade. At low gate and high drain voltages, the device exhibits injection of holes from the Al drain electrode. This was rectified by using LiF as a buffer layer between Al and (PTCDI-C13H27). Such modified devices exhibited mobility 1.2 x 10(-2) cm(2) V-1 s(-1), threshold voltage -0.3 V, and inverse subthreshold swing of 5 V/decade. © 2005 Elsevier B.V. All rights reserved.