Cyanocobalamin (vitamin B 12 ) is an essential nutrient as well as a very useful carrier in drug delivery. Conjugates of vitamin B 12 are investigated due to their wide range of therapeutic applications. We report the synthesis of six vitamin B 12 conjugates, and the effect of conjugation on their solubilities and stabilities in various media. We reveal here that vitamin B 12 can be released readily if a 2′-hydroxyl group is conjugated rather than the 5′-hydroxyl group, and the solubility (thus the equivalents of vitamin B 12 ) could be enhanced as much as 19-fold, by simple conjugates such as glycolates. Findings disclosed here provide insights into the reactivities of vitamin B 12 conjugates, the design of future prodrugs and similar conjugated moieties using vitamin B 12 .