Tetraphenylsilane derivatives attached with one to four of N,N-diphenylaninooxadiazole(TPAOXD) blue fluorescent moieties, namely Si(PhTPAOXD)4, PhSi(PhTPAOXD)3, PH2Si(PhTPAOXD)2, and Ph3Si(PhTPAOXD), were synthesized and characterized. Tetraphenylsilane core structure provides an effective molecular skeleton for inhibiting the crystallization of the material. Very bright blue electroluminescence (>20,000 cd/m2) was observed for a trilayer device with configuration of ITO/NPB/PH3Si)PhTPAOXD)/Alq3/Mg:Ag. The electroluminescence of the device, in terms of emission wavelength and chromaticity, is highly dependent on the thickness of emitting layer. The current-voltage-electroluminescence characteristics of the devices are described.