We report the synthesis of new conjugated compounds, 10,10'-Bis(4-tert-butyl-Phenyt)-10H, 10' H-[3,3'] biphenothiazinyl(t-BPBP), 10'-(4-tert-Butyl-Phenyl)- 10' H [ 10, 3'; 7' 10'] terphenothiazine (t-BPTP), 10, 10'-Bis-(4-tert-Butyl-Phenyl)-7,7' diphenothiazyl-10H, 10' H-[3,3'] biphenothiazinyl (t-BPDPBP). The obtained compounds were identified by 1H-NMR, IR and FAB-Mass spectroscopy. All the compounds exhibited high glass transition temperature (T-g) in the range of 118-161 degrees C. The glass transition and crystallization temperature of these materials appear to be rather high among commonly used hole injection material (m-MTDATA). Electro-optical properties were characterized by cyclic voltammetry and photoluminescence spectra. Organic Electro-Luminescence (EL) device with configuration of ITO/t-BPBP (60 nm)/NPB (15 nm)/Alq3 (70 nm)/LiF (1 nm)/Al (200 nm) exhibits a current efficiency 4.53 cd/A and power efficiency of 1.88 lm/W at 10 mA/cm(2) current density. (c) 2005 Elsevier B.V. All rights reserved.