According to a previous study, an exchange reaction between [Au25(PET)18] -NCs and PDTH2 yields a mixture of Au25(PET)18-2x(PDT)x NCs (x = 2-6) rather than a single main product, such as [Au25(PET)12(PDT)3] -. By analyzing the NC mixture using matrix-assisted laser desorption ionization-MS and performing DFT calculations of a hypothetical [Au25(PDT)9] -NC, the authors predicted that an inter-staple PDT exchange between nearest core-apex positions preferentially occurs over an inter-staple exchange between nearest core-core positions. Interestingly, the present SCXRD analysis of PDTH2-exchanged 4 resulted in an opposite trend to that obtained from the prior work described above. In the present study, each PDT moiety was preferentially connected to two nearest staples (RS-Au-SR-Au-SR, where SR = TBBT) through interstaple core-core substitution (Figure ).