Macroporous poly(lactic acid) with inverse opal structure (IoPLA) was fabricated by colloidal crystal templating. IoPLA shows an intense near-infrared (NIR) reflection, which comes from the optical diffraction upon the periodic macroporous structure composed of uniformly sized pores. It is demonstrated that in vivo implantation of IoPLA leads to destruction of the inverse opal structure. causing a notable decrease in the intensity of the NIR reflection peak. IoPLA with this degradation-dependent optical property might become an implantable photonic bandgap material that can report the state of degradation and co-occurring events in a nondestructive, real-time manner.