Tri-​component multi-​functional boronated complexes (B-​complexes)​, featuring reversible covalent bonds, are described, which incorporate a drug;a water-​sol. moiety (e.g. polyethylene glycol (PEG) chains, cyclodextrins)​;and a targeting unit. A B-​complex core was assembled in one step, and proved to be stable in different biocompatible conditions, such as human plasma, though reversible for example in the presence of glutathione (GSH)​. This platform enabled the modular construction of the multifunctional conjugates exhibiting high selectivity towards, for example, folate- receptor-​pos. MDA-​MB-​231 cancer cells, having an IC50 in the low nanomolar range.