Organic light-emitting diodes (OLEDs) were widely used about not only the displays such as televisions, smartphones, etc. but also the lighting equipment and organic laser devices. The emitter materials with 100% internal quantum efficiency have been reported, and the external quantum efficiency of devices has reached around 40%. However, the development of operating with low voltage has been limited. We recently reported about the OLEDs operated by ultra-low voltage and call them to exciplex upconversion type OLEDs (ExUC-OLED). Here, we introduce the operating mechanism and the latest results about ExUC-OLEDs with orange and blue emissions. These operated voltages were shown about half the value of the energy gap (eV) of the emitter divided by the elementary charge (e).