Cyclodextrins are multi-faceted molecules capable of assuming versatile roles in the detection of metal ions through electronic absorption spectroscopy and colorimetric methods. In spectrophotometry-based metal sensing, cyclodextrins have been employed via three main approaches: (1) The formation of chelation complexes between metal ions and structurally modified cyclodextrins, where the modification enhances the binding affinity for specific ions. (2) The creation of inclusion complexes, where cyclodextrins encapsulate guest molecules that serve as signaling groups for metal ions. (3) Functionalisation of nanoparticles with cyclodextrins. In all three approaches, the interaction between metal ions and cyclodextrins—whether through direct chelation, inclusion complex formation, or nanoparticle functionalisation—induces observable changes in the absorption spectrum of the sensor. This chapter examines the role of cyclodextrins in each of these three approaches, with a focus on how specific chemical modifications are introduced to enable the selective detection of metal ions. The chapter also correlates the resulting spectral changes and colorimetric responses, to the underlying mechanistic processes that occur during metal ion interaction, providing a comprehensive understanding of how these modifications influence the detection performance of cyclodextrin-based sensors.