1,4-Diphenyl-3-thiosemicarbazide is an organic compound with the molecular formula C13H12N4S. It appears as a white to light yellow crystalline solid and is known for its diverse biological activities, particularly in medicinal chemistry. This compound serves as a versatile building block in the synthesis of various thiosemicarbazone derivatives, which exhibit notable pharmacological properties, including antimicrobial, anticancer, and antiviral effects.