Two novel tetrahalogeno-4,4'-bi-1,2,4-triazoles, tetrachloro-4,4'-bi-1,2,4-triazole (1, TCBTr) and tetrabromo-4,4'-bi-1,2,4-triazole (2, TBBTr) were successfully synthesized through halogenation of 4,4'-bi-1,2,4-triazole (BTr) and structurally characterized by elemental analysis, IR, C-13 NMR and MS spectra. The single crystals of title compounds were cultivated and determined with X-ray diffraction, and the test results reveal that the aromatic pi center dot center dot center dot pi stacking interactions between molecules and the tetrahalogeno-4,4'-bi-1,2,4-triazoles with the two triazole rings being perpendicular are well observed in the crystal structure of (1) and (2).