The title compound phenyl(6-phenyl-3-p-tolyl-6,7-dihydro-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-7-yl)methanone (PTM),designed using 4-amino-3-p-tolyl-1H-1,2,4-triazole-5(4H)-thione as the starting material,was successfully synthesized via a two-step synthesis route and fmally characterized by NMR,FT-IR,single-crystal X-ray diffraction and mass spectrometry techniques.The crystal structure of trans-PTM was obtained from X-ray diffraction: C24H20N4OS,Mr =412.52,monoclinic system,space group P21/c,a =16.650(3),b =13.876(3),c =8.812(2) (A),β =100.340(3)°,V=2002.8(7) (A)3,F(000) =865,Z =4,Dc =1.3680 g/cm3,λ =0.71073 (A),μ =0.186 mm-1 and the final R =0.0786 for 3514 unique reflections with 2044 observed ones (Ⅰ ＞ 2σ(Ⅰ)).The biological activities of antimicrobial and regulation of plant growth of PTM were investigated.The results indicated that PTM showed weak antimicrobial activity on Bacillus pumilus,while promoted the growth of radish and inhibited that of wheat in a dose-dependent manner.Therefore,PTM may be developed as a potential drug to promote the growth of dicotyledonous plants or as an herbicide to inhibit that of monocotyledonous plants in the future.