This document summarizes research on supramolecular receptors for technetium pertechnetate (TcO4-) and rhenium perrhenate (ReO4-) ions. Key findings include: - Rigid macrocyclic receptors that allow multiple hydrogen bonding and ionic interactions strongly bind TcO4- and ReO4- outside the cavity. ReO4- can be used as a template for macrocycle synthesis. - Hydrophobic cavitands containing positively charged metal fragments like ruthenium or iron efficiently extract TcO4- and ReO4- from water due to ion exchange and hydrophobic interactions. - Smaller receptors still show selectivity through hydrogen bonding,