New host material of 2-tert-butyl-9,10-bis(3,5-diphenylbiphenyl-4-yl)anthracene [T-TAT] substituted t-butyl group was investigated in solution process WOLED device compared with 9,10-bis (3,5-diphenylbiphenyl-4'-yl) anthracene [TAT]. A two-color WOLED of a co-host system using solution process method was demonstrated. The device configuration was ITO / PEDOT:PSS (40nm) / emitting layer (50nm) / TPBi (20nm) / LiF (1nm) / Al. The emitting layer consisted of TAT or T-TAT, NPB, DPAVBi (blue dopant), and rubrene (yellow dopant). NPB was used to help hole carrier transport as well as blue host role. The device using the T-TAT compound as a co-host showed a luminance efficiency of 2.73 cd/A, which is 77% higher than TAT device of 1.54 cd/A at 20mA/cm(2).