The new generation of optoelectronics seeks for emerging semiconductors which combine high performance with low cost. Lead halide organic-inorganic perovskites manifest as excellent optoelectronic materials for this purpose, but at the expense of robustness and environmental compatibility. This presents a major challenge which this research addresses directly. Viable alternatives have to be identified. To tackle this challenge, MIX2FIX proposes to develop a new class of solution-processable optoelectronic devices based on air-stable, non-toxic metal chalcogenides endowed with an organic part, which will facilitate solution-processing and potentially enrich the compounds with the spectacular properties of halide perovskites. To achieve this, the CoG project has set the following objectives: (i) designing and developing optoelectronically-active, organic-inorganic chalcogenide thin films films that have never been explored before, by mimicking strategies from established perovskite technology, (ii) devising means to improve their optoelectronic quality so as to be comparable with the best single-crystal semiconductors and (iii) implementing optimized materials into boundary-pushing PV and LED devices. Addressing these objectives will enable the development of novel functional hybrids at the boundaries of perovskite and chalcogenide thin films. With this, optoelectronics with efficiency and stability, comparable or higher than those of lead halide perovskite or chalcopyrite devices, will be demonstrated. This project will therefore permit the transition for emerging optoelectronic materials from toxic lead halide perovskites to green hybrid chalcogenides. Consolidating this unproven but disruptive technology will secure sustainable future for other areas of interest beyond photovoltaics, displays and lighting such as in X-Rays detectors and phototransistors or even beyond optoelectronics, in systems such as batteries and supercapacitors.