Abstract: A novel and convenient synthetic method for 1-phenyl-3-substituted phenyl-4-triazolyldihy-dropyrazoles(1a-1b) and 3-substituted phenyl-4-triazolyldihydropyrazole (7) from α-triazolyl-β-alkoxyacetophenone 4 was described. The reaction condition was studied and optimized. 1,3,4,5-Multi substituted dihydropyrazole 1c-1h were prepared through the general cyclization of α, β-unsaturated ketone with phenylhydrazine and their structures were confirmed by ¹H NMR, MS and elemental analysis. Furthermore, 3,5-substituted dihydropyrazole 6(or 7) reacted with methyl(or ethyl) chloroformate and potassium thiocyanate to afford 1,3,5-(or 4-)substituted dihydropyrazole 2a-2l. The results of preliminary bioassay presented that almost all compounds showed fungicidal, herbicidal and plant growth regulatory activities.

Key words: Dihydropyrazole, Synthesis, Bioactivity