The self-assembly of (TMEDA)Pd(NO3)(2) or (TMEDA)Pt(NO3)(2) (where TMEDA = N-1,N-1,N-2,N-2-tetramethylethane-1,2-diamine) and anthracene-or ferrocene-based diimidazole ligands (L1-3) in aqueous solution affords a series of positively charged [M2L2](4+) dimetallomacrocycles. Their structures were characterized by H-1 NMR and electrospray ionization mass spectrometry and in the cases of {[(TMEDA)Pd](2)L-2(1)}(NO3)(4) (1), {[(TMEDA)Pd](2)L-2(1)}(PF6)(4) (1a), and {[(TMEDA)Pd](2)L-2(3)}(NO3)(4) (4) by single-crystal X-ray diffraction analysis. Interestingly, the NMR spectra of 1 and la revealed that the difference of their structures, as confirmed by X-ray diffraction analysis, was that a NO3- of 1 was encapsulated inside the cavity of the basket-shaped metallomacrocycle by C-H center dot center dot center dot O hydrogen bonds, while PF6- of 1a was bound outside by C-H center dot center dot center dot F hydrogen bonds. The fluorescence titration experiment exhibited the formation of 1:1 host guest complexation for anthracene-based positively charged [M2L2](4+)-type metallomacrocycles with NO3-. The interactions between metallomacrocycles and various anions were investigated via fluorescence titration and cyclic voltammetry studies, respectively.