<p>A series of novel antimony(III) halide complexes with thiophene-based thiosemicarbazone ligands were synthesized in a 2:1 ligand-to-metal molar ratio via refluxing in methanol. The molecular formulations of the seven newly obtained complexes are as follows: [SbCl₂(μ₂-Cl)(κ¹-S-Hattsc)₂]₂, [SbBr₂(κ¹-S-Httsc)(κ²-N³,S-Httsc)], [SbBr₂(μ₂-Br)(κ¹-S-Hattsc)₂]₂, [SbI₂(κ¹-S-Htmtsc)(κ²-N³,S-Htmtsc)], [SbI₂(κ¹-S-Htetsc)(κ²-N³,S-Htetsc)], [SbI₂(κ¹-S-Hatmtsc)(κ²-N³,S-Hatmtsc)], and [SbI₂(κ¹-S-Hatetsc)(κ²-N³,S-Hatetsc)]. The structures of the synthesized complexes were confirmed by a combination of techniques, including melting point determination, molar conductivity measurements, elemental analysis, FT-IR, FT-Raman, UV–Vis spectroscopy, as well as ¹H and ¹³C NMR spectroscopy. Thermal stability was assessed through thermogravimetric and differential thermal analyses (TG–DTA). The antimicrobial activities of the complexes were evaluated against both Gram-positive (<i>Staphylococcus aureus</i> ATCC 29213, <i>Streptococcus mutans</i> ATCC 25175, <i>Enterococcus faecalis</i> ATCC 29212) and Gram-negative bacteria (<i>Escherichia coli</i> ATCC 25922, <i>Pseudomonas aeruginosa</i> ATCC 27853, and <i>Salmonella typhimurium</i> ATCC 14028). Notably, the complexes exhibited superior antimicrobial activity against <i>E. coli</i>, <i>S. typhimurium</i>, and <i>S. mutans</i> compared to the standard antibiotic gentamicin.</p> Graphical abstract <p></p>