Bis(۲-ethylheptyl) phthalate is an anti-oxidant and anticancer compound that was extracted from the Cynodon dactylon plant stem extract and fully identified and characterized by FTIR, CHN, ۱HNMR, ۱۳CNMR, along with various ۲D NMR techniques. The phthalate compound was modified and functionalized by polyethylene glycol (PEG) chains followed by complexation to Cu(II) ions. The resultant complex was applied as an efficient and strong recyclable homogeneous catalyst for the preparation of ۱,۸-dioxo-octahydroxanthenes under mild conditions. The homogeneous catalyst could be recovered and reused for several times.