EN
Photoinduced optical second harmonic generation was demonstrated in the several dithiole chromophore molecules with different degree of acceptor function. Theoretical quantum chemical simulations and experimental photoinduced second harmonic generation measurements showed that additional aromatic rings within the dithiole chromophore molecule play an important role in the pump-power dependencies of the second harmonic generation. Varying the presence of the aromatic rings one can achieve substantially different photoinduced second-order nonlinear optical properties.