The thin-film transistor characteristics of n-channel organic semiconductor, N,N-'-bis(2,2,3,3,4,4,4-heptafluorobutyl)-perylene tetracarboxylic diimide, are described. The slip-stacked face-to-face molecular packing allows a very dense parallel arrangement of the molecules, leading to field-effect mobility as high as 0.72 cm(2) V-1 s(-1). The mobility only slightly decreased after exposure to air and remained stable for more than 50 days. Our results reveal that molecular packing effects such as close stacking of perylene diimide units and segregation effects imparted by the fluorinated side chains are crucial for the air stability. (C) 2007 American Institute of Physics.