The energy spectra of one-dimensional (1-D) stacks consisting of large pi-pi interacting polycyclic aromatic hydrocarbons (PAH) have been investigated theoretically with the Bloch band theory, taking into account electron correlation. It is shown that the band gap DeltaE is different from zero (DeltaE > similar to0.8 eV) for 1-D stacks consisting of PAHs with different topology, symmetry, and a number of pi-centers N less than or equal to 10(2), i.e., the ground state of the stacks is a dielectric one.