Orthoxylene is used as part of the manufacturing process to make phthalic anhydride (which is used to make PVC and other plastics), anti-bacterial compounds, and herbicides.

structural formula of ortho-xylene:

      H        H
       \      /
        C == C        H
       /      \      /
 H -- C        C -- C -- H
       \\    //      \
        C -- C        H
       /      \
      H        C -- H     ortho-xylene
              / \         C8H10
             H   H