A straightforward strategy has been used to construct large BN-embedded pi-systems simply from azaacenes. BN heterosuperbenzene derivatives, the largest BN heteroaromatics to date, have been synthesized in three steps. The molecules exhibit curved pi-surfaces, showing two different conformations which are self-organized into a sandwich structure and further packed into a pi-stacking column. The assembled microribbons exhibit good charge transport properties and photoconductivity, representing an important step toward the optoelectronic applications of BN-embedded aromatics.