Single crystals of linear fused rings with nitrogen heteroatom, indolo[3,2-b]carbazole (ICZ), have been synthesized. In addition, field-effect transistors (FETs) of planar ICZ single crystals have been fabricated. The hole mobility approaches values of up to 1.0 cm2 V−1 s−1 with an on/off ratio of ∼106. The transistors exhibit sensitivity to nitric oxide (NO). The gas-sensitive behavior indicates the great potential for future low-cost and high-density storage devices.