A method of patterning large arrays of organic single crystals is reported. Using single-walled carbon nanotube (SWNT) bundles as patterned templates, several organic semiconductor materials were successfully patterned, including p-type pentacene, tetracene, sexiphenylene, and sexithiophene, as well as n-type tetracyanoquinodimethane (TCNQ). This study suggests that the selective growth of crystals onto patterned carbon nanotubes is most likely due to the coarse topography of the SWNT bundles. Moreover, we observed that the crystals nucleated from SWNT bundles and grew onto SWNT bundles in a conformal fashion. The dependence of the number of crystals on the quantity of SWNT bundles is also discussed. The crystal growth can be directly applied onto transistor source-drain electrodes and arrays of organic single-crystal field effect transistors are demonstrated. The results demonstrate the potential of utilizing carbon nanotubes as nucleation templates for patterning a broad range of organic materials for applications in optoelectronics.