a thickness of 150 nm by using another vacuum vapor deposit device to manufacture an oled after forming a hole injection layer and a hole transport layer according to the same procedure as example 8 4 4 u2032 n n u2032 dicarbazole biphenyl cbp was charged thereon as el host material while 1 phenyl isoquinoline was charged to another cell as conventional red el dopant the two materials were evaporated at different rates to give doping and provide vapor deposition of an el layer having the thickness of 30 nm on the hole transport layer the doping concentration preferably is from 4 to 10 by weight on the basis of the host then bis 2 methyl 8 quinolinato p phenylphenolato aluminum iii balq was vapor deposited as a a hole blocking layer with a thickness of 10 nm and a hole blocking layer an electron transport layer and an electron injection layer were vapor deposited according to the same procedure of example 6 by using another vacuum vapor deposit device an al cathode was vapor deposited thereon with a thickness of 150 nm to manufacture an oled the operation voltage and red luminous efficiency of the oled 39 s comprising the organic el compound according to the present invention examples 8 to 10 or conventional el compound comparative example 3 were measured at 10 ma cm 2 respectively and the results are shown in table 5 when compounds 101 121 and 136 according to the invention are employed the device exhibits comparable efficiency properties to that using a conventional el host and provides good color coordinate in addition noticeable effect of lowered power consumption of the oled due to lowered operation voltage by 0 8 to 1 1 v.