Three heterocyclic diazenyl compounds were synthesized by diazotization of 3-aminopyridine and aniline, followed by coupling with 8-aminoquinoleine, morpholine, 1,2,3,4-tetrahydroquinoleine, respectively. The obtained azo compounds are brown to yellow in color and were characterized by various methods such as NMR and X-rays. The synthesized compounds were evaluated for their antimicrobial activity against Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans. The MIC of the tested compounds, determined by the microdilution method, showed potential antimicrobial activity against all tested microorganisms. 1-(3-pyridyl)-2-(morpholin-4-yl)diazene ( 8) and 1-(3-pyridyl)-2-(tetrahydroquinolin-1-yl)diazene (10) showed strong activities against C. albicans with MIC values of 150 µM and 120 µM respectively. 1-(4trifluoromethylphenyl)-2-(8-aminoquinolin-5-yl)diazene (4) showed the broadest spectrum of activity with good MICs of 1380-2760 µM on the four strains. These diazenyl compounds were also screened for their anticancer activity against breast (MCF-7), lung (Calu-3), pancreas (PANC-1) and prostate (PC-3) cancer cells and on normal fibroblasts. The results showed good anticancer activities on tumor lines with IC 50 values ranging from 9.4 to 98 µM. The best anticancer activity was obtained with compound 4 on Calu-3 cancer cells with an IC 50 of 9.4 µM. The results suggest that compound 4 is an interesting scaffold for pharmacomodulation as suggested by ADME study.