Bilayer-type layered herringbone (LHB) packing is of great importance because of its remarkably high layered crystallinity and its ability to form extremely smooth ultrathin films which are useful for printed electronics technologies. Here we discuss the origin of the high layered crystallinity in the bilayer-type LHB packing, through the reliable crystal structure analysis of a novel unsymmetrically alkylated benzothienonaphthothiophene (BTNT) derivative.