Antifungalagent 129 (Compound 4g) acts as an inhibitor against Rhizoctonia solani, with an EC50 value of 4.27 mg/L. It shows effective control of rice sheath blight in both in vitro and in vivo studies. Preliminary investigations using scanning electron microscopy, molecular docking, enzyme activity assays, and cytotoxicity tests suggest that Antifungalagent 129 may exert its inhibitory action by affecting the cell structure or physiological processes of Rhizoctonia solani. This compound has potential applications in agricultural research related to plant diseases caused by Rhizoctonia solani, such as rice sheath blight.