Aqueous indocyanine green (ICG) composition exhibiting enhanced stability, as well as enhanced ICG concentration, as compared to presently available ICG products. The composition comprises an aqueous ICG composition comprising ICG at a concentration of at least about 10 mg/ml and an aqueous diluent, wherein the composition is stable for at least 24 hours. Diagnostic and therapeutic methods for using these aqueous compositions are also contemplated, e.g., angiography, dye-enhanced photocoagulation, photodynamic therapy, for a variety of conditions, including Age-Related Macular Degeneration (ARMD), lesions and tumors.