Tri-component multi-functional boronated complexes (B-complexes), featuring reversible covalent bonds, are described, which incorporate a drug; a water-soluble 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-positive MDA-MB-231 cancer cells, having an IC50 in the low nanomolar range.