New thiazole and thiazolopyrimidine derivatives 2-13 were synthesized and estimated for antimicrobial efficacy on S. aureus, B. cereus, E. coli, C. albicans, A. fumigatus 293 and A. terreus. The obtained results proved that compounds 3 and 10 have significant activity toward S. aureus and B. cereus, whereas 2, 11 and 13 exhibited good activity over B. cereus. E. coli was significantly sensitive to compound 10. From another point of view, 11 and 13 exhibited promising efficacy over A. fumigatus 293 and A. terreus. Quorum-sensing inhibitory activity of the new compounds was esteemed over C. violaceum ATCC 12472, where 3, 4, 8, 9b, 9d, 10, 11 and 13 have acceptable efficacy. In vitro antitumor effectiveness of the new analogs against liver (HepG2), colon (HCT-116) and breast (MCF-7) cancer cells was also assessed. Compounds 2 and 7 showed outstanding effectiveness over the three cell lines, whereas 11 displayed eminent activity toward HCT-116 and MCF-7 cells. Moreover, 3 and 9d were found to have good activity against MCF-7 cells. The in vitro active antitumor analogs were assessed for in vivo antitumor effectiveness over EAC in mice, as well as cytotoxicity toward WI38 and WISH normal cell lines. The active antimicrobial and antitumor members were investigated for DNA-binding affinity, where 2, 7, 10 and 11 showed the strongest affinity. In silico studies proved that majority of the analyzed compounds meet the optimal requirements for good oral absorption.