The intrinsic zero band gap structure and semi-metallic character of graphene has some limitations for applications in photonic devices. In this regard, the optical properties of graphene need to be tuned by functionalization followed by heteroatom doping and reducing the lateral dimensions up to a few nanometres. Further, the fluorescence quantum yield of ‘as prepared’ graphene quantum dots has been significantly improved by doping with the combination of heteroatoms. The charge transfer (CT) interaction in low dimensional systems and laser dyes have significant importance in various fields. The feasibility of non-radiative resonance energy transfer (RET) between heteroatoms co-doped NS-GQD-dye system has also been explored. The NS-GQD fluorescent nanoprobe has been found suitable to detect the H2O2 and deep tissue imaging applications as well. In addition, the low dimensional systems were also probed with high intensity laser to understand the nonlinear optical responses for passive mode-locking application perspective.