COMMUNICATION (1 of 8)self-standing crystals, like formation of cracks (even macroscopically invisible ones) and/or bad physical contact with the underlying substrate due to surface irregularity of the latter. Moreover, thanks to several centuries of development in the printing industry (the first reported print by J. Gutenberg is dated around 1450), this technology ensures very low production costs and high throughputs. Among the printing techniques that can be used with OSSCs, a particularly interesting one is inkjet (IJ) printing, which allows to rapidly deposit the desired compound only on selected parts of the substrate, minimizing material losses and increasing the overall process productivity. In the last 15 years, IJ printing of organic semiconductors has been explored, and examples of devices based on IJ-printed organic semiconductors and conductors include transistors, [12,13] organic ligth-emitting diodes (OLEDs), [14,15] different types of sensors, and biosensors. [16][17][18][19] These devices have been mainly realized taking advantage of polymers as the active materials, while in some cases soluble organic small molecules, that form highly polycrystalline thin films, have been used. Recently, some attention has been paid to IJ printing of molecules able to produce OSSCs, but such a growth from a small drop of IJ-deposited solutions is not straightforward. The crystallization mechanism at work in this case is the so-called "slow solvent evaporation," in which the solvent slowly evaporates, creating a supersaturation condition that results in nucleation and subsequent crystal growth. However, when this phenomenon occurs in very small volumes (as in the case of IJ-printed solutions, i.e., in the range of a few microliter to hundreds of microliter), a number of undesired processes can arise, like solution spreading on the substrate, or uncontrolled multiple nucleation or accumulation of material at the edges of the drop (the so-called coffee ring effect). [20] These phenomena, which result in the formation of polycrystalline films, are particularly evident when the drops are deposited onto highly heterogeneous substrates, as for example lithographically defined interdigitated electrodes. Jang and co-worker reported the IJ printing of polycrystalline films of TIPS-pentacene (6,13-bis(triisopropylsilylethynyl)pentacene, from now on TIPS), [21] a high-performing molecular semi conductor that delivers top charge-carrier mobilities exceeding 6 cm 2 V s −1 , [22] but usually in the range of 0.5-1 cm 2 V s −1 . [23,24] Interestingly, Organic semiconducting single crystals (OSSCs) are very promising for lowcost electronics, being the highest performers among organic semiconductors in terms of charge transport, with carrier mobilities exceeding 10 cm 2 V s −1 . Here, it is demonstrated how it is possible to obtain millimeter-long single crystals of 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) onto gold interdigitated electrodes patterned onto flexible plastic substrates, via direct inkjet printin...