While mature solar technologies (i.e. photovoltaics, photo-electrochemical cells) cannot simultaneously address the multi-faceted future energy challenge, PLANKT-ON aims to develop a disruptive net-zero emissions technology to both address the global energy demand and reoxygenation of our planet. Inspired by Nature, we propose to assemble the first synthetic plankton-like protocells that autonomously utilise light, water, and CO2 to produce O2 and formate, as a green H2 vector. To this aim, the plankton-like protocells will be shaped as containers of two synergic subdomains mimicking the natural plastids and the CO2-enzyme organelles. The artificial plastid (1st type proto-organelle) will utilise light to oxidise H2O to O2 and reduce a methyl viologen (MV) cofactor, this latter will feed the CO2-rich proto-organelle to selectively produce formate by a cascade enzymatic reaction. We are expecting that this original bio-inspired strategy will open a route to sustainable solar hydrogen. The long term impact is envisaged for scientific innovation in groundbreaking solar-technology, going beyond the conventional photoelectrochemical cabled asset, and readily exploitable for empowering the EU vision for “Smart Buildings as Micro-Energy Hubs” in the world. Fundamental Research advances will be monitored by PLANKT-ON innovation radar activities, protected by our IP policy and disseminated to reach the expected stakeholders and the general public. Multidisciplinary collaboration among the 6 partners, from 4 EU countries, 5 research centres, and 1 technology-based company, underpins the project activities that will target the EU mission. PLANKT-ON counts on the valuable experience of its Scientific Advisory Committee where international renowned scientists from Princeton (USA), Berkeley (USA), Tokyo (Japan) and EPFL-Lausanne (Switzerland) will contribute to the results evaluation and benchmarking in the field of light management, photo-catalysis and green H2 transport.