This entry is adapted from 10.3390/jcs7010026. Hydrogels are hydrophilic, three-dimensional networks able to imprison large amounts of water and are largely used in pharmaceutical formulations. Hydrogels are frequently obtained from hydrophilic polymers, either natural, biohybrid, or synthetic. Phosphorus dendrimers possessing high multivalency provide the favorable positioning of functional groups at the surface, as well as cavities, in the three-dimensional organization of the scaffold and, therefore, can be considered potential gelators. The internal structure of phosphorus dendrimers is hydrophobic, whereas their terminal functions can be positively or negatively charged; thus, the whole structure becomes amphiphilic.