This work presents a rational synthesis of 14 innovative methyl salicylate based thiazole (MSBT) derivatives, designed as protein tyrosine phosphatase 1B (PTP1B) inhibitors with potent anticancer activity. Enzyme inhibition studies were performed for all compounds. In addition, molecular docking simulations and assessment of antiproliferative activity were performed for the most active of the lot. For antiproliferative studies, the cell lines of breast cancer (T47D) and non-small-cell lung carcinoma (A549), as well as healthy control of human skin fibroblasts (HSF), were used. As a result, 3 compounds were found to inhibit the PTP1B enzyme in submicromolar concentrations: 3j (IC