A dual-signal probe PPN based on the natural β-pinene derivative nopinone was synthesized for the colorimetric detection of Cu²⁺ and ratiometric detection of Ag⁺. Upon the addition of Ag⁺, a significant fluorescence change from blue to green was observed with a low detection limit (0.86 μM). However, upon the addition of Cu²⁺, a significant color change from colorless to yellow was observed with a low detection limit (0.56 μM). The novel probe PPN was applied as a probe for the colorimetric detection of Cu²⁺ and ratiometric detection of Ag⁺ with a high selectivity, good sensitivity and fast response time. The detection mechanisms of probe PPN for Cu²⁺/Ag⁺ were confirmed by ¹H NMR and HRMS-ESI. Besides, probe PPN could sense Cu²⁺/Ag⁺ on test strips. Additionally, probe PPN could be applied to quantitatively detect the concentration of Ag⁺ in water samples and image Ag⁺ in living cells.