We demonstrate low operating voltage (<|1.5| V) chemical vapour deposited (CVD) graphene transistors using solution processable organic self-assembled monolayers (SAMs) as nanodielectrics. The transistors show weak extrinsic doping, hysteresis-free operation, low gate-leakage current and good operating stability with bias-stress free characteristics. Most importantly we demonstrate that the Dirac potential can be finely tuned by modifying the molecular end-group of the SAMs without compromising the electrical characteristics of the transistors.