5-Aryl-4-cyano-1H-1, 2, 3-triazoles bearing a variety of substituting groups on 5-phenyl were synthesized. Their structures were established by MS, IR and 1H NMR spectra. The crystal structures of compounds 3f and 3m were determined by X-ray diffraction analysis. The active H of the triazole was on 1-N from the crystal structures. The compounds, designed as HER2 tyrosine kinase inhibitors, were screened for bioactivity of growth-inhibition of breast cancer MDA-MB-453 cells. The lowest IC50 value of inhibiting HER2 tyrosine kinase phosphorylation in breast cancer cells is 6.6 micromol x L(-1). The inhibiting-growth of breast cancer cells was enhanced from electron-drawing groups joining 5-phenyl on the triazole.