The field of plastic electronics has the potential to enable useful devices, such as flexible paper-like displays, woven elec-trotextiles, low-cost identification tags, etc., which might be difficult to achieve with conventional inorganic materials and processing technologies. Progress in this area is driven partly by the development of high-speed printing approaches and associated materials that can be used to pattern circuits over large areas at low cost. Several techniques have been explored , including the photochemical conversion of polymers from non-conducting to conducting states, [1] specialized adaptations of ink jet [2] and screen printing, [3,4] certain types of molding [5,6] and imprinting [7] approaches, and a nanotransfer printing method. [8,9] Microcontact printing [10] has been shown to be useful for patterning gold and silver source/drain electrodes and interconnects in large-area flexible circuits for paper like displays and other devices. [11,12] We recently reported a purely additive thermal transfer printing technique that is capable of directly patterning multiple layers of organic electronic materials with micrometer (~ 5 lm) resolution over large areas (well over 3 m 2) and with multilevel registration (maximum misregistration of < 200 lm over the entire > 3 m 2 printed area). [13] In this approach, conducting polymers are transfer printed, layer by layer, from donor sheets onto a circuit substrate using localized laser-induced heating. This method has a completely dry, solventless operation that avoids many of the problems associated with chemical incompatibilities that commonly arise in solution-processed multi-layer plastic circuits. For many envisioned applications in large area displays and other systems, the circuits are simple enough that registration errors and multilevel stack integrity are not limiting. In addition, for these applications the ability to print lines with better than ~ 25 lm resolution rapidly and over large areas begins to enable circuits that could have some commercially significant applications even with existing organic semiconductors. The performance, of course, benefits not only from high-resolution printed electrodes (i.e., short transistor channel lengths), but it also relies critically on low resistance coupling of the electrodes to the semiconductor layers. (It also depends, of course, on good dielectrics, [14] semiconductors , and other factors that are not the focus of this manuscript.) This paper examines the remarkably good contacts that form when pentacene and copper hexadecafluor-ophthalocyanine (FCuPc) are deposited onto printed dinonyl-naphthalene sulfonic acid doped polyaniline/ single-walled carbon nanotube (DNNSA-PANI/SWNT) electrodes to produce n-and p-type transistors and complementary inverter circuits. The …