Despite continuous active development of fluorescent probes for metal-ions, their molecular design for ratiometric detection is limited owing to a narrow choice of available sensing mechanisms. We present herein a dual-emission sensing platform for metal ions based on contact interaction between a coordinated metal ion and the aromatic ring of a fluorophore (i.e., arene–metal-ion contact). Our structure-based ligand design provided a new probe possessing BPTN as the metal ion binding unit, which was flexibly concatenated to a tricyclic fluorophore. This molecular architecture allowed us to fluorescently sense various metal ions such as Zn(II), Cu(II), Cd(II), Ag(I), and Hg(II) with the red-shifted emissions. This probe design was applicable to a series of tricyclic fluorophores, enabling ratiometric detection of the metal ions across the blue to near-infrared wavelength region. X-ray crystallography and theoretical computational calculation indicated that the coordinated metal ion has van der Waals contact with the fluorophore, which perturbs its electronic structure and ring conformation to induce the emission red-shift. A set of the arene–metal-ion contact probes was used for the differential sensing of eight metal ions in a one-pot single titration via PCA analysis. Furthermore, the probe was applicable to the ratio imaging of metal ions under live-cell conditions.