We have realized tuning of electronic memory-switching property via functional group modification in solid-state devices. Apart from their large ON/OFF ratio and long memory retention time, solid-state devices sustain repetitive switching between the two ON/OFF states at high frequencies. We have chosen several molecular systems with same backbone structure and tuned ON/OFF ratio from 4 to 300 000 simply by increasing the number of deactivating groups. A key to the large ON/OFF ratio in these devices has been the presence of acceptor groups in the molecules and consequently low OFF state current. We analyzed the appearance of ON state in terms of conjugation restoration of the molecules. A redox active group has been found to be necessary in the molecules for continuous flip-flop between "1" and "0" states for random access memory (RAM) applications.