Temperature is a fundamental parameter in any chemical process, affecting reaction rates, selectivity and more. In this regard, photon-assisted heat generation for chemical reactions utilizing photothermal materials is emerging as an exciting tool for innovative research. Herein, we develop a synthesis and in-situ assembly strategy for metal-organic frameworks (MOFs) based on the distinct heating of photothermal materials under visible light. A simple cobalt chloride molecular complex is utilized as an efficient and stable light-to-heat converter for initial MOF formation. A thorough investigation of the assembly mechanism reveals the key role photothermal conversion has in the synthesis of the superstructures. Finally, palladium nanoparticles (PdNPs) are utilized as competing photothermal agents (PTAs) shedding light on the dynamics between different heat sources within a reaction and resulting in MOF-NP composites. This work highlights the versatility of the photothermal approach in the synthesis of advanced materials introducing a promising route to the micro/nano assembly of different materials.