The aim of this research was to develop a method for synthesizing 1,2-thiodisaccharide-type galectin inhibitors with a C-galactopyranosyl-heterocyclic unit. To achieve this, a cyanogalactal was used as a key intermediate which was synthesized from D-galactose in a three-step reaction. The cyanogalactal underwent an elimination reaction to obtain the galactal derivative. The derivative was then reacted with different thiols to give the desired galactal–benzothiazole hybrid.