Abstract The Fourier-transforn method of calculating polarization energies for localized charges is extended to treat molecules as sets of submolecules. This takes account of molecular size, shape and orientation, and is essential to obtain results for highly anisotropic molecules in an internally consistent way. Results are presented for naphthalene and anthracene, and (for the first time) for benzene, biphenyl and p-terphenyl; with each aromatic ring treated as a submolecule, variations between crystals are mostly small. Concentrating the excess charge on one ring gives polarization energies of typically −1.3 to −1.4 eV, whereas spreading the charge uniformly over all rings gives −1 to −1.2 eV. Combined with calculatedion-quadropole energies, these results can be compared with experimental values from photoemission andphotoconductivity studies. They imply iattice relaxation energies of −0.2 to −0.4 eV.