Promoting electron mobility is the key to designing high performance electron transport materials (ETMs). Formation of intermolecular interaction can be helpful to enhance their electron mobilities as a result of more ordered molecular stacking. Here, to reveal the inherent influence of intermolecular π-π stacking on the electron mobilities, we designed two ETMs, namely, 2,4-diphenyl-6-[3-(2-triphenylenyl)phenyl]-1,3,5-triazine (TPTRZ) and 2,4-diphenyl-6-[4′-(2-triphenylenyl)[1,1′-biphenyl]-3-yl]-1,3,5-triazine (TPPTRZ). Thermal, photophysical and electrochemical measurement results indicate they are good ETM candidates. Additionally, TPTRZ and TPPTRZ exhibit high electron mobilities of 3.60×10−5 and 3.58×10−5 cm2 V−1 s−1, respectively, at an electric field of 7×105 V cm−1. By taking X-ray single crystal structure, theoretical calculation and time of flight (TOF) results into consideration, it is revealed that strong intermolecular π-π stacking induced by planar triphenylene and triphenyltriazine units renders TPTRZ and TPPTRZ small energetic and positional disorder parameters, and results in their high electron mobilities thereby. By further enhancing intermolecular π-π stacking, ETMs with even higher electron mobilities can thus be anticipated.