We propose a way of patterning organic small molecule thin films without requiring a hardmask and therefore more compatible with printing technologies. Active and passive areas for transistors are predefined by different surface chemistries. The subsequent growth takes place under conditions that cause the formation of a high mobility two-dimensional film in the active area and a disconnected three-dimensional film or no film in the passive area. This concept is founded on the basic theory of nucleation of organic small molecules on inert substrates and applied to the growth of patterned pentacene layers. (C) 2004 American Institute of Physics.