Here, we introduced cobalt chloride as an efficient photothermal agent for obtaining assemblies of Co-DHBDC also known as MOF-74-Co (Fig. , and Supplementary Fig. ). Initially, we set out to test whether the photothermal method could be utilized to obtain well defined MOF superstructures as we have previously shown for nanoparticles (NPs). We thus envisioned that if the molecular precursor and resulting MOF had an overlap in absorption with substantial contribution from MOF, we could utilize a single wavelength to both initiate MOF formation and in-situ produce assemblies. Thus, we searched for a suitable synthesis procedure and came across Co-DHBDC. From the absorption spectra we found 520 nm to be the suitable wavelength as we hypothesized, thus we irradiated a solution of cobalt chloride in presence of DHBDC, and were thrilled to find that assemblies indeed formed (Fig. , and Supplementary Figs. ).