Abstract <p>The present study aimed to synthesize and characterize a group of novel phenylthiazoles and, finally, discovered their antioxidant and antimicrobial efficacy in reducing infectious diseases. The agar disk diffusion method evaluated their antimicrobial efficacies against fungal strains (<i>Aspergillus niger</i>, <i>Trichoderma harzianum</i>), gram-positive (<i>Staphylococcus aureus</i>, <i>Bacillus megaterium</i>), and gram-negative (<i>Salmonella typhi</i>, <i>Escherichia coli</i>) bacterial strains. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and total antioxidant capacity (TAC) methods were used to measure their antioxidant efficacies. Among the tested analogs, we detected the maximum antifungal efficacy for 4-{[2-(4-phenylthiazol-2-yl)hydrazineylidene]methyl}phenol, followed by 2-[2-(4-chlorobenzylidene)hydrazineyl]-4-phenylthiazole. Nevertheless, 5-bromo-2-{[2-(4-phenylthiazol-2-yl)hydrazineylidene]methyl}phenol produced the lowest inhibition zone against <i>T. harzianum</i>. However, the antifungal efficacies for the synthesized compounds were significantly higher than the standard amphotericin B. In contrast, the highest efficacy of the compound 4-{[2-(4-phenylthiazol-2-yl)hydrazineylidene]methyl}phenol is 1.3 times greater than Amphotericin B. Besides, the highest antibacterial efficacy was detected for 4-{[2-(4-phenylthiazol-2-yl)hydrazineylidene]methyl}phenol, followed by 2-[2-(4-chlorobenzylidene)hydrazineyl]-4-phenylthiazole, which was 0.4 times lower than standard ceftriaxone. Moreover, the lowest inhibition zones were achieved for 5-(diethylamino)-2-{[2-(4-phenylthiazol-2-yl)hydrazineylidene]methyl}phenol. The antioxidant screening was done using DPPH free radical inhibition capability and TAC methods. However, both methods ensured that 5-(diethylamino)-2-{[2-(4-phenylthiazol-2-yl)hydrazineylidene]methyl}phenol is a highly potent antioxidant.</p>