We report the synthesis and characterization of two novel polyimides (PIs), PI(2,8-APDBT-6FDA) and PI(3,7-APDBT-6FDA), consisting of alternating electron-donating 2,8- or 3,7-phenylenesulfanyl-substituted dibenzothiophene and electron-accepting phthalimide moieties for high-performance memory device applications. The optical band gaps of PI(2,8-APDBT-6FDA) and PI(3,7-APDBT-6FDA) films were 3.40 and 3.31 eV, respectively, indicating the significance of the linkage position. The device with the ITO/PIs/Al configuration showed the multimemory characteristics changing from high-conductance ohmic current flow to nonvolatile negative differential resistance (NDR), dynamic random access memory (DRAM), and insulator, with the corresponding film thickness of 12, 20, 25, and 45 nm, respectively. Both PIs exhibited similar memory characteristics, but PI(3,7-APDBT-6FDA) with a lower threshold voltage due to its high-lying HOMO energy level. The 20 nm PIs device exhibited the nonvolatile behavior with the NDR region a...