The design and synthesis of several new bis-thiazoles 4a–h serving as bis-drugs in comparison with mono-heterocyclic analogs are described. These bis-drugs present superior medicinal and pharmacological activities against both gram-negative (Pseudomonas aeruginosa and Escherichia coli) and gram-positive (Micrococcus luteus and Bacillus subtilis) bacteria, which are in general more sensitive to compounds with ...