A new series of non-peptidic, mono-acid protein tyrosine phosphatase 1B (PTP1B) inhibitors has been identified by structure-based design. Compounds with 2-(indol-3-yl)-and 2-phenyl- 3, 3, 3-trifluoro-2-hydroxypropionic acid core units targeted at the enzyme's primary site and a hydrophobic chlorophenylthiazole extension in its 2° site exhibit 3–60μM IC50s for PTP1B inhibition in an Sf9 cell-based assay.