A series of long-chain N-arylundecanamides containing benzimidazole thioethers (2a-e) were synthesized and characterized by FT IR, H-1 NMR, and elemental analysis. The corrosion inhibitory properties of these compounds on cold rolled low carbon steel metal coupons were investigated by weight loss measurements in acidic media. Surface characterization studies of the metal coupons used were performed by contact angle measurements using the sessile-drop method. In addition, the 3D image of the metal surface was measured using an optical profilometer. The results obtained from these analyses showed that almost all of the tested compounds between 25-150-ppm concentrations in acidic media are good to excellent corrosion inhibitors with the values of percentage inhibition efficiency () = 77-99%. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.