Porphyrins are photosensitisers used in photodynamic therapy (PDT) due to their tumor localization and in situ singlet oxygen generation. However, their limited absorption, insolubility, and aggregation in an aqueous medium limited their effective application in PDT. To overcome these limitations, we herein, report a large-scale aqueous synthesis of CuInS2/ZnS ternary quantum dots, and its conjugation to 5, 10, 15, 20-meso(4-hydroxyphenyl) porphyrin. The singlet oxygen generation of this highly aqueous soluble novel conjugate shows its potential for PDT applications.