Pentacene crystallizes in a layered structure with a herringbone arrangement within the layers. There exist several polymorphs of pentacene. Identification of these pentacene polymorphs is especially important as the electronic properties depend strongly on the stacking of the molecules within the layers. In this paper the intermolecular potential energy of the pentacene crystal is represented by Born-Mayer-Haggins pair potential model. We have performed electronic band structure calculation based on the tight-binding model for the two polymorphic crystal structures of pentacene. The calculated bandwidth reduction in going from 0K to room temperature is of the order of 8%—14%.