A series of novel imine-linked 1,3,4-thiadiazole derivatives were rationally designed and synthesized via Schiff base condensation to explore their antibacterial potential. The synthetic strategy aimed to integrate the pharmacologically active thiadiazole nucleus with an azomethine (–CH=N–) linkage to modulate electronic properties and enhance biological activity. The synthesized compounds were characterized by FT-IR, ¹H NMR and mass spectrometry. The analytical and spectral data confirmed the proposed structures and indicated satisfactory purity of the compounds. In vitro antibacterial activity was evaluated against Gram-positive strains (Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus mutans) and the Gram-negative strain (Escherichia coli) using agar diffusion and broth micro-dilution methods. Ciprofloxacin was employed as the reference standard. Among the synthesized derivatives, eight compounds exhibited significant antibacterial activity. Compounds TZ3 and TZ5 demonstrated the highest zones of inhibition and TZ5 and TZ10 shown lowest minimum inhibitory concentration (MIC) values, indicating superior antibacterial efficacy within the series. Preliminary structure–activity relationship analysis suggested that substituent variations significantly influenced antimicrobial potency. These findings identify imine-linked thiadiazole derivatives, particularly TZ3, TZ5 and TZ10 as promising antibacterial lead molecules for further optimization.