Exploration and comprehension of chemical bonding is one of the central tasks in chemistry. Here, a non-covalent interaction, a nido-cage···? bond, is discovered in a collaborative work between Deshuang Du and Prof. Yan from Nanjing University and Prof. Jordi Poater at the University of Barcelona (ex-IQCC) and Prof. Miquel Solà of IQCC (Univ. Girona). The