Solid state lighting industry is booming in recent years because of the green energy requirement. Therefore, phosphorescent OLEDs using phosphorescent emitters doped into charge-transporting hosts as emissive layers (EMLs) have attracted extensive interest due to their highly efficient emission compared to conventional fluorescent OLEDs, through radiative harvesting of both electro-generated singlet and triplet excitons. To achieve better charge balance and device performance, many researchers focus on developing new phosphorescent host materials with bipolar charge transporting property. In this work, we successfully designed and synthesized a host material CzppT containing hole-transporting carbazole and electron-transporting pyridine and investigated the physical properties. With a high triplet energy, CzppT is considered a promising universal host material and has been applied to phosphorescent OLEDs of blue/white colors. Blue/white OLEDs based on CzppT as host and Firpic/Ir(piq)2(acac) as dopant materials show maximum external quantum efficiencies (11.0% for blue, 11.32% for white) and CIE coordinates [(0.18,0.41)for blue, (0.32,0.36) for white)]. The results indicate that the bipolar host CzppT with high triplet energy has potential in manufacturing blue and white OLEDs for display or lighting applications.