The ab initio molecular orbital calculations have been carried out to clarify the molecular planarity of the B and C polygonal membered ring (MR) clusters by varying their charged states as well as spin configurations. The highly anionization or higher spin states enhances the planarity of the BC skeleton because of an increase in the number of the occupied pi bonding orbitals (BOs). Moreover, the BC polygonal networks composed of 6MR or 5-7MR units prefer to form the electron attracting stages.