Carbon-carbon bond is one of the most ubiquitous molecular building blocks for natural and man-made materials. Rotational isomerization is fundamentally important for understanding the structure and reactivity of chemical and biological molecules. Reported herein is the first demonstration that a single C-C bond does not rotate in water. The two distal C-S bonds in both 1,2-ethanedithiolate (S--CH2-CH2-S-, 1,2-EDT2-) and 2,3-butanedithiolate (2,3-BuDT2-) are exclusively in the trans conformer with reference to their respective center single C-C bond. In contrast, both trans and gauche conformers are observed in neutral 1,2-ethanedithiol (1,2-BuDT2-) and 2, 3-butanedithiol (2,3-BuDT). The insight from this work should be important for understanding the charge effect on the molecular conformation in aqueous solutions.