Random copolyimides, PI-PBIX, with different compositions of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), N,N'-bis(4-aminophenyl)-3,4,9,10-perylenebis(dicarboximide) (PBI), and 4,4'-diamino-4 ''-methyltriphenylamine (AMTPA) were designed and synthesized for resistive-switching memory device applications. By varying the feeding ratio of monomers, PI-PBIX (where X = 0, 1, 2.5, 5, and 10 for molar composition of repeating units containing PBI) showed tunable optical and electronic properties through the charge transfer between AMTPA and Pill. Also, the memory devices prepared from PI-PBIX sandwiched between ITO and Al electrodes exhibited the tunable electrical bistability from the volatile to nonvolatile write once read many-times (WORM) memory characteristics as the PBI composition increased. The OFF/ON electrical switching transition was mainly attributed to the charge-transfer mechanism for charge-separated high conductance, based on the analysis of density function theory. Also, the volatility of PI-PBTX. device depended on the stability of charge-transfer complex and charge trapping sites. The deep LUMO energy level of the PBI moiety increased the back-charge-transfer energy barrier and prevented recombination of segregated charges even through applying the high negative and positive voltage. The study revealed that the memory characteristics could be tailored from the donor acceptor composition in the random copolyimides.