Site-directed electrochemical deposition of pinhole free, low-k dielectric thin films on graphene is described for the first time. Specifically, we demonstrate the heterogeneous electrochemical polymerization of phenol to form thin (3-4 nm) layers of poly(phenylene oxide) (PPO) on monolayer graphene samples prepared by micromechanical exfoliation and chemical vapor deposition growth. We demonstrate the reliability of depositing PPO films simultaneously on a large number of devices, and selected individual graphene flakes/devices. The performance of top-gated field effect transistor devices described herein demonstrates the utility of electrodeposited PPO films as a top-gate dielectric.