Rhodamine B (Rh—B) is a well-known carcinogenic agent with potential health risks, yet it is frequently used as a food adulterant in developing countries. This study presents the synthesis and characterization of a Broussonetia Zeylanica extract (BZ-EXT) from a plant for the rapid, efficient, and sensitive colorimetric sensing of Rh—B. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.41 μg/mL and 1.31 μg/mL, respectively. We demonstrating superior sensitivity compared to conventional methods using DI water as a solvent. Furthermore, the practical applicability of the developed material was successfully tested in real samples, yielding estimated values of Rh—B are 0.76 μg/mL and 0.52 μg/mL, respectively. The pH dependent colorimetric sensing performance of the BZ-EXT for Rh—B detection was found more efficient at aqueous pH value of 9.2. These results highlight the potential of the BZ-EXT as a promising tool for rapid and sensitive detection of Rh—B food adulteration in real samples.