Abstract
Molecular simulation based on density functional theory was performed on the structure of anthraquinone, pentacenequinone, heptacenequinone and their dianions. The HOMO-LUMO gap, excitation energy and absorption wavelength were calculated to examine the switching action of molecules via two electron OX/RED reaction. Drastic change has been found in HOMO-LUMO gap, excitation energy and absorption wavelength of neutral molecules and their dianions. It has been observed that these three poly-acenes based organic molecules are very auspicious for the design and manufacturing of redox-active molecular switches.