Transfer of water-insoluble photochrome to the aqueous environment results in its aggregation, as presented by Sun and co-workers, who used nanocrystalline cellulose as a platform for hydrophobic spirooxazine derivative. Our material does not contain any clumps of Azo, as confirmed by TEM (Figure ). Our protocol enables uniform impregnation of nanofibers and assures homogenous nature of the hybrid material. CNFs ensure system's stability, and the as-prepared AzoGly-Au-2-CNFs composite maintains its dual plasmonic-photochromic functionality. The presence of both functional units is distinctly visible on the UV-Vis-NIR absorption spectra (Figure ). The intensities of the π→π * and n→π * photochromic bands in a solvent in which AzoGly is not soluble clearly confirm the success of the proposed material design in transferring Azo properties to the new environment. We attribute small differences in their positions and profiles compared with pristine AzoGly (Figure ) to the solvent change and interactions with CNFs. Plasmonic bands of Au-2 (transverse, t-LSPR and longitudinal, l-LSPR) are distinct, well separated, and not distorted. Slight spectral shifts (3 nm blueshift for t-LSPR and 18 nm redshift for l-LSPR, Figure ) are observed. We attribute this to the change in the effective refractive index due to the CTAB exchange at the surface, especially at the AuNRs' tips. In our case, CTAB is replaced by CNFs. In principle, we distinguish three different spectral regions of the sample as marked on top of corresponds with partially overlapping Azo n→π * band and t-LSPR band of Au-2. AzoGly undergoes Z-E isomerization when irradiated in close proximity to the n→π * band, e.g. 500-600 nm (Figure ). This precludes us from further use of region (2) in the plasmon-assisted experiments.