1,4-Dichlorobenzene (p-DCB or para-dichlorobenzene, sometimes abbreviated as PDB or para) is an organic compound with the formula C₆H₄Cl₂. This colorless solid has a strong odor. In terms of its structure, the molecule consists of two chlorine atoms substituted for hydrogen at opposing sites on a benzene ring. p-DCB is used as a pesticide and a deodorant, most familiarly in mothballs in which it is a replacement for the more traditional naphthalene due to its flammability. p-DCB is also used as a precursor in the production of the polymer poly(p-phenylene sulfide).