GRETA will lay the foundation of the first green, printed and flexible organic wireless identification tag operating at Ultra-High Frequency (UHF, 300 MHz – 1 GHz). The long-term vision is to enable remote powering and readout of tags up to meters distance range, as required in logistics and security, without the need of a battery and with drastically reduced lifecycle impact and costing with respect to any available passive radio-frequency identification (RFID) technology. To achieve such overarching goal, GRETA aims at groundbreaking progress along two specific complementary actions: - Action 1: Removing present barriers preventing sustainability of printed organic electronics, by tackling the most environmental and economically impactful aspects, yet seldom addressed, of organics synthesis and processing. - Action 2: Demonstrating unprecedented UHF operation of printed organic electronics. Measurable objectives of GRETA are: Objective 1. Green synthesis and development of sustainable and biodegradable materials (Action 1); Objective 2. Sustainable inks formulations for large-area printing tools (Action 1); Objective 3. UHF electronics based on sustainable printed organic semiconductors (Action 2); Objective 4. Enable an eco-designed, printed UHF wireless tag with sustainable lifecycle. Objective 4 is dedicated to demonstrators of the entire effort: GRETA UHF tag, demonstrating rectification of a 400 MHz wave to enable a code generator, and GRETA UHF logic, demonstrating a sustainable printed integrated 4-bit shift register. GRETA perfectly matches the scope of the Call as it serves emerging digitalization needs in logistics, healthcare and security without adding e-waste, independent from the silicon industry and from any critical raw material, and delivering safe materials for the environment. GRETA will quantify its drastically reduced environmental impact with a full LCA, along a cradle-to-grave approach, anticipating end-of-life scenarios.