A new class of carbazolo[2,1-a]carbazole diimide compounds (CBZCBZ-DI, 3) are designed and synthesized. The synthesis, X-ray crystal structure, absorption spectra, and electrochemical properties of 3 as well as the charge transport properties are investigated. Theoretical calculation is also carried out based on the X-ray crystal structure of 3a to understand the relationship between the structure and the charge transport properties. Single-crystal X-ray analysis revealed that the molecules of 3a adopt a slipped face-to-face pi-stacking mode with a large intermolecular pi-overlap and an interplanar distance of 3.4 angstrom. Crystalline transistors of 3a display high hole mobility of 0.5 cm(2)V(-1) s(-1), which is among the highest reported mobility values for carbazole-based N-heteroacenes. Two useful brominated derivatives (4, 5) are also prepared for synthesizing more new pi-functional materials.