Eye drops are envisaged as the most promising non-invasive formulation for the treatment of the ocular posterior segment diseases, while it is hindered by a series of complex ocular barriers, both static and dynamic in nature. In this context, we propose a single molecule nanomedicine based on host-guest chemistry to achieve highly efficient drug delivery targeted to ocular posterior segment. Sulfonated azocalix[4]arene (SAC4A) serves as the single molecule carrier, owing the multiple features of small size (24.0 Å in length, 21.2 Å in width, 14.8 Å in height with a Van der Waals volume of 930 Å