In　this　study,　the　synthesis　of　TaN　nanosheets　and　their　application　in　theranostic　agents　is　reported.　After　coating　polyethylene　glycol　(PEG)　on　the　TaN　nanosheets,　the　as-synthesized　PEG-modified　TaN　nanosheets　(TaN-PEG)　show　good　stability　and　biocompatibility.　Because　of　their　high　absorbance　in　the　near-IR　region,　TaN-PEG　can　be　utilized　as　photoacoustic　imaging　contrast　agents　for　tumor　imaging.　Moreover,　TaN-PEG　has　significant　photothermal　conversion　performance,　exhibiting　effective　laser-induced　tumor　ablation　capability.　The　TaN-PEG　possessing　excellent　photoacoustic　contrast　effect　and　photothermal　properties　thus　have　great　promise　in　theranostic　applications,　especially　imaging-guided　cancer　treatment.　©　2021　Wiley-VCH　GmbH.