Multifunctional biodegradable nanomaterials that could be used for both imaging and therapy are being researched extensively. A simple technique to synthesize multifunctional nanoparticles without compromising on any of their functionality is a challenge. We have attempted to optimize a two-step procedure of gold coated polymeric template involving 1) Single pot synthesis of PLGA nanoparticles with cationic surface charge using glycol chitosan and 2) in situ gold coating for formation of gold coated PLGA nanoshell (AuPLGA-NS). These gold-coated PLGA nanoparticles were explored for photothermal therapy (PTT) and as X-ray/CT contrast agents. Biocompatibility and photothermal cytotoxicity of AuPLGA-NS were evaluated in-vitro and results confirmed the therapeutic efficacy of these particles resulting in 80% cancer cell death. Besides, it also showed potential X-ray/CT imaging ability with contrast equivalent to that of Iodine. The results demonstrated that these gold-coated PLGA nanoparticles synthesized by a simple approach could be used as a multifunctional nanosystem for cancer theranostics. © 2017 Elsevier B.V.