Herein, we describe the synthesis of thiomaltooligosaccharides by the complete regio- and stereoselective photoinitiated thiol-ene coupling reaction of 2-acetoxy-glucal and 4-thioglucose type reaction partner, using methyl 2,3,6-tri-O-acetyl-4-S-acetyl-4-thio-α-D-glucopyranoside (12) as a unique starting material.