Fluorescence imaging technology strongly relies on imaging contrast agents. In particular, organic luminogens with second near-infrared region (NIR-II, 1000-1700 nm) absorption and emission are highly desirable contrast agents due to their excellent biocompatibility, deep penetration depth and high imaging contrast . Although organic NIR-II luminogens have demonstrated their significant applications as fluorescent contrast agents, the commonly used commercial imaging contrast agents like ICG suffer the problem of concentration quenching effect, which means they can only be used in low concentration since high concentration will diminish and even quench the emission . Low concentration administration and rapid hepatobiliary clearance result in a significantly reduced imaging window of ICG (less than 5 minutes) , which is inadequate to guide a 3.5 -5 hours of kidney transplant surgery. Although the photostability of the molecular contrast agents could be improved by preparing their nanoaggregates, the aggregation mostly reduced the brightness of traditional planar luminogens including ICG, which limit their application for long-time surgical process imaging and monitoring. In this regard, NIR-II luminogens with high brightness, long-circulating time, and high photostability in aggregates are highly desirable.