o-Chloranil, also known as 3,4,5,6-tetrachloro-1,2-benzoquinone, is a yellow crystalline organic compound. Structurally, it is a chlorinated derivative of ortho-benzoquinone, featuring four chlorine atoms substituted at the 3, 4, 5, and 6 positions of the benzene ring. It is a strong oxidizing agent and is used primarily as an intermediate in organic synthesis, particularly in dye manufacturing, pharmaceuticals, and agrochemicals.