Fused-ring electron acceptors (FREA) for organic solar cell applications have rapidly developed in recent years whose absorption wavelength mainly locate in NIR region with superior lightharvesting capability . However, the luminescence properties of these materials have scarcely been investigated and applied in biomedical area. In this work, by learning from the molecular design of FREA, we designed and synthesized two-expanded molecules DIPT-IC and DIPT-ICF with rigid and planar conjugation structures. The results indicate that both DIPT-IC and DIPT-ICF exhibit NIR-II emission and AIE property with superior absorptivity and high PLQYs, which endow them with high brightness and superior photostability in aggregates. Water soluble nanoparticles of DIPT-IC and DIPT-ICF thus were prepared and applied in monitoring and evaluation of the entire process of kidney transplantation. The results indicate that a single dose of DIPT-ICF NPs contrast agent could monitor the entire surgical process very clearly via luminescence, which is much better than the commercial contrast agent ICG. This study demonstrates that fluorescent imaging technology based on NIR-II contrast agents is a promising approach to monitor the whole process of organ transplantation surgery and diagnose the possible surgical complications, which would work as a reliable approach to assist surgeons to improve the success rate of renal transplantation.