Phenylene group
Image:P-phenylene-group-2D-skeletal.png|thumb|right|The chemical structure of the para-phenylene group.
In organic chemistry, the phenylene group is based on a di-substituted benzene ring. For example, poly(p-phenylene) is a polymer built up from para-phenylene repeating units. The phenylene group has three structural isomers, based on which hydrogens are substituted: para-phenylene, meta-phenylene, and ortho-phenylene.
[Image:Ortho-meta-para.svg|thumb|150px|right|Isomer naming convention]