A fluorescent chemosensor including dual Bodipy units (d-BODIPY) was improved for selective copper (II) sensing in half-aqueous samples. The sensor d-BODIPY has a highly selective and sensitive detection towards Cu (II) over the studied competing for metal cations. The interaction among solutions of Cu (II) and d-BODIPY caused a crucial quenching effect in fluorescence maxima at 548 nm (λex = 470 nm) owing to the electronic trap occurring between the amide and triazole units. The quenching effect without any change in wavelength can be explained by a photoinduced electron transfer (PET) process. The binding constant (Ka) of d-BODIPY with Cu (II) was calculated and also the limit of detection of d-BODIPY for Cu (II) was 1.2 × 10−8 M. In addition, the bio-imaging in the yeast cells suggested that d-BODIPY had an excellent potential to be used to investigate Cu (II).