Cell‐penetrating peptides (CPPs) are excellent cell internalizing agents for hydrophobic drug/dye moieties. We exploited this property of CPPs for the cell internalization of BF₂‐oxasmaragdyrin by constructing covalent conjugates of BF₂‐oxasmaragdyrin with CPPs (CRGDK and polyarginine (R₉)) using a solid‐phase peptide synthesis (SPPS) methodology. The CPP‐conjugated BF₂‐oxasmaragdyrins were purified by reversed‐phase HPLC and characterized by mass spectrometry. The CPP‐conjugated BF₂‐oxasmaragdyrins were found to be photostable, absorb in the visible‐NIR region (400–700 nm), emit in the NIR−I region (∼715–720 nm) with moderate quantum yields, and be biocompatible, with excellent cellular imaging potential in breast cancer cells (MDA‐MB‐231). The R₉ conjugate, being the first water‐soluble BF₂‐oxasmaragdyrin, also possesses excellent photothermal transduction efficacy with 750 nm laser irradiation and is a potential theranostic agent.