To illustrate the applicability of the NDI polymer platform, we designed a stimuli-responsive system with photochromic fluorescence and evaluated its performance for proof-of-concept information encryption. Anthracene is known to undergo [4 + 4] cycloaddition when exposed to light above 340 nm, and the resulting dimer can be cleaved by light below 300 nm or by heat . We hypothesized that the NDI copolymers with a high anthracene fraction would exhibit a considerable light-controlled emission color shift, due to the structural variation-mediated TSCT process. To validate our hypothesis, we selected NDI-coAntMA with a 5.2% anthracene monomer loading (PAM feed = 2.5%), and measured its PL spectra in solid films upon 365-nm UV irradiation at various time intervals.