This study explores the development of tunable afterglow materials for self-monitoring 3D printed structures. Two organic molecules, DTPPAO and tBuDTPPAO, with a twisted donor-acceptor-acceptor (D-A-A') configuration are designed and synthesized. These molecules exhibit dual-emissive afterglow with tunable lifetimes (86.1–287.7 ms) when doped into various matrices. By using a photosensitive resin, complex 3D structures are fabricated using 3D printing technology. The mechanical properties of these structures, such as Young's modulus, can be controlled by manipulating the photocuring time and humidity level. With sufficient photocuring or in dry conditions, the structures exhibit a long-lived bright green afterglow without significant deformation under external loading. This work demonstrates the potential of using organic afterglow materials for real-time monitoring of mechanical properties in 3D printed devices, offering opportunities for flexible and self-monitoring 3D printing applications.This study explores the development of tunable afterglow materials for self-monitoring 3D printed structures. Two organic molecules, DTPPAO and tBuDTPPAO, with a twisted donor-acceptor-acceptor (D-A-A') configuration are designed and synthesized. These molecules exhibit dual-emissive afterglow with tunable lifetimes (86.1–287.7 ms) when doped into various matrices. By using a photosensitive resin, complex 3D structures are fabricated using 3D printing technology. The mechanical properties of these structures, such as Young's modulus, can be controlled by manipulating the photocuring time and humidity level. With sufficient photocuring or in dry conditions, the structures exhibit a long-lived bright green afterglow without significant deformation under external loading. This work demonstrates the potential of using organic afterglow materials for real-time monitoring of mechanical properties in 3D printed devices, offering opportunities for flexible and self-monitoring 3D printing applications.