Due to the importance of biological activities of 1,2,4-triazine derivatives, in this manuscript, ten of newly synthesized compounds containing 1,2,4-triazine moiety were prepared. Anticancer and antimicrobial activities of some selected synthesized compounds were screened. Chalcone derivatives 6, 7 were synthesized via reaction of Mannich base 2 in acetic acid and fused sodium acetate with formyl khellin 5 or vanillin. Treatment of chalcone derivatives 6, 7 toward hydrazine hydrate, phenyl hydrazine, hydroxylamine hydrochloride or malononitrile, respectively, led to give pyrazoline 8, 9, 10, 11, oxazole 12, 13 and pyridine 14, 15 derivatives, respectively. The structures of the isolated products were established by elementary analysis and spectral data studies. Compounds 1, 5, 6, 8, 10, 12 and 14 were tested against different human cancer cell lines, and cytotoxicity in vitro and most of the synthesized compounds were proved to have high activities against cytotoxic test. Then, the compounds 1, 5, 6, 8, 10, 12 and 14 were tested against cancer in vivo, and the result was established. Also, antimicrobial activity of compounds 1, 5, 6, 8, 10, 12 and 14 was screened in vitro against a panel of gram-positive and gram-negative bacterial pathogens and fungi. The results indicated that compound 5 showed higher antimicrobial activity than compounds 1, 6, 8, 10, 12 and 14, and compound 5 exhibited a wide range of antimicrobial activities against gram-positive and gram-negative bacteria and fungi, greater than well-known antibacterial and antifungal agents with minimal inhibitory concentration ranged between 6.25 and 25 μg.