Cryogenic transmission electron microscopy (Cryo-EM) was conducted to investigate the morphologies of organic nanoparticles used in this study. According to Cryo-EM both NPs looked amorphous without clear signs of layered or crystalline structure. Specifically, the freshly prepared POZ-M(-) NPs had a spherical porous morphology, while POZ-M(+) NPs had elongated hollow morphology (Fig. ). However, under photocatalytic conditions in the presence of CO 2, Cryo-EM studies revealed that both POZ-M(-) NPs and POZ(+) NPs underwent morphology change from spherical and elongated hollow morphology respectively (Fig. ) into nanorods (further denoted as NRs) architectures with more pronounced crystalline structure (Fig. ). Morphology changes most likely originate from the seaweed-type orientation of the hydrophobic chains of lightharvesting POZ-M molecules. As similar morphology change was observed for both positively and negatively charged NPs in the presence of Ar as a carrier gas, it was suggested that NRs are the thermodynamic product of POZ-M NPs (Fig. ). POZ-M(-) NRs as well as POZ-M(+) NRs are offering an accessible surface for interaction with the enzyme.