Highly-efficient blue organic light-emitting devices with a nondoped device structure have been fabricated with two anthracene derivatives, 2,3,6,7-tetramethyl-9,10-(1-dinaphthyl)-anthracene (α-TMADN) and 2,3,6,7-tetramethyl-9,10-(2-dinaphthyl)-anthracene (β-TMADN). The homemade α-TMADN, β-TMADN, or their blend were used as the light-emitting materials, and 4,7-diphenyl-1,10-phenanthroline was used as the hole blocking and electron transporting material, N,N′-biphenyl-N,N′-bis-(1-naphenyl)-[1,1′-biphenyl]-4,4′-diamine was used as the hole transporting material. The brightness of the device with β-TMADN as the light-emitting material is up to 10 000 cd/m2 at 12 V with the maximum efficiency of 4.5 cd/A, which is better than that of the device with α-TMADN as the light-emitting material. The brightness of the same structure device with the blend of α-TMADN and β-TMADN as the light-emitting material, in which the ratio of α-TMADN to β-TMADN is 9:1, is more than 12 000 cd/m2 at 15 V with the maximum efficiency of 5.2 cd/A. © 2004 American Institute of Physics.