An inclusion complex of a trigonal-prismatic metallacage with two coronene guests was constructed by multicomponent coordination-driven self-assembly from a 90° platinum(II) acceptor [cis-Pt(PEt3)2(OTf)2], disodium terephthalate, and 2,4,6-tri(4-pyridyl)-1,3,5-triazine in the presence of excess coronene. This platinum(II)-based trigonal prism was found to be a highly matched host to simultaneously encapsulate two coronene molecules. The encapsulation of coronene can effectively promote the formation of a pure single-prismatic metallacage and can stabilize the self-assembled structure via strong π-π-stacking interactions between coronene and the metallacage.