Developing colorimetric devices for detecting chemical species is essential in many fields; nevertheless, developing effective chemosensors for many heavy and transition metal ions remains an important issue. As a result, in recent years, the use of colorimetric sensors for the selective and sensitive detection of metal ions has grown in popularity. Pyrazolones and its derivatives are heterocyclic compounds that have attracted interest due to their biological and pharmacological features. As a result, they have been used in various areas, including agriculture, medicine, organic synthesis, and analytical chemistry. However, the potential for chemosensing has yet to receive much attention. In this study, thiomethyl substituted (4Z)-4-[(pyrazol-4-yl)methylene]pyrazolone was synthesized, and its ability to act as an optical chemosensor for several metals was evaluated. According to preliminary results, this molecule could be an optical chemosensor to detect Fe³⁺, Sn²⁺, and Al³⁺.