Organic light emitting bistable memory devices (OLEBDs) with a dual function of organic light emitting diodes and organic memory devices were developed by using 0.5 nm thick MoO3 as an interlayer between hole injection layer and hole transport layer. The hole transport unit with MoO3 interlayer played a role of a memory unit as well as a hole transport unit. High on/off ratio over 1000 was obtained at a reading voltage of 1 V and driving voltage was lowered by MoO3. In addition, two different luminances were obtained at the same driving voltage by changing writing voltage of OLEBDs. (C) 2008 American Institute of Physics.