Thiophenols are a class of volatile aromatic compounds containing sulfur. Thiophenols mostly have a unique flavor. Benzenethiol (PhSH), for example, is described as having a meaty, smoky, garlic and other flavors, and is widely used in the preparation of everyday dishes as a common condiment. Nevertheless, the abuse of thiophenols can present a significant risk to human health. In order to ensure food safety and life health, it is crucial to develop a method for accurately analyzing exogenous invasive thiophenols in common foods and cells. In this paper, a novel small molecule fluorophore ethyl (E)-2-(3-(2-(6-hydroxynaphthalen-2-yl)vinyl)-2-oxoquinoxalin-1(2H)-yl)acetate (QN-OH) was designed, and 2, 4-dinitrophenoxy was attached to the fluorophore as the recognition site of PhSH, and finally the probe ethyl (E)-2-(3-(2-(6-(2,4-dinitrophenoxy)naphthalen-2-yl)vinyl)-2-oxoquinoxalin-1(2H)-yl)acetate (QNF) was obtained. The probe shows a ratiometric response towards PhSH, with a low detection limit down to 6.3 nM. QNF was successfully applied to detect thiophenols in both food samples and cells. This study shows that QNF is an effective tool for detection of thiophenols.