The authors investigated the efficiency and chromatic-stability characteristics of organic light emitting devices (OLEDs) with ultra-thin yellow emissive layers of 0.1 nm 5,6,11,12,-tetraphenylnaphthacene (rubrene) and hole block layer of BCP. The OLEDs with double thin rubrene layers and BCP layer were found to exhibit a high luminance and electroluminescence (EL) efficiency. The maximum EL efficiency and luminance reached 6. 35 cd x A(-1) at 6 V and 7 068 cd x m(-2) at 10 V respectively. Moreover, Commission International De L'Eclairage (CIE) coordination maintained unchanged (0.49, 0.49) in the wide range of applied voltages. The enhanced efficiency and good chromatic stability were attributed to a balanced injection and transport of electrons and holes and the expected confinement and balanced recombination of the emission region in the ultra-thin rubrene layers.