Two luminescent materials with 1,3,6,8-tetramethylcarbazole (TMCz) donors and 1,3,4-oxadiazole (OXD) or 1,3,4-thiadiazole (THD) acceptor, namely TMCz-OXD and TMCz-THD, were designed and synthesized. The photophysics, electrochemical properties and electroluminescence were characterized by UV-vis absorption and emission spectroscopy and electrochemical analysis. Experiment results show the steric hindrance caused by two methyl groups on the 1,8 sites of TMCz can effectively increase the dihedral angle (86?) between donor and acceptor. Both doped films of TMCz-OXD and TMCz-THD exhibited thermally activated delayed fluorescence (TADF) character. And the external quantum efficiencies (EQEs) of the corresponding electroluminescence were 6.5% and 6.4%, respectively. As a versatile blue TADF material donor, TMCz can be applied widely in the field of organic light-emitting diode (OLED).