NAMPT activator-6 is a NAMPT activator, a regulatory molecule for the optical control system of NAMPT and NAD+. NAMPT activator-6 can be used to design efficient photoswitchable proteolysis-targeting chimeras (PS-PROTACs) to achieve up-down reversible regulation of NAMPT and NAD+ in a light-dependent manner and reduce the toxicity associated with inhibitor-based PS-PROTACs. PS-PROTAC can be used to achieve antitumor activity, NAMPT , and NAD+ modulation in vivo via optical manipulation.