Proteins are a paradigm materials programmed to optimize their bio-functionality (fluorescence, redox behaviors, catalytic activity, transport phenomena, etc.) in living organisms. While we have mastered an excellent genetic toolbox to tune protein functionality in-vivo for imaging, sensing, etc., their stabilization has been unsuccessful, limiting the progress of the emerging protein-based optoelectronic technologies, such as lighting and photovoltaic devices, with respect to device fabrication using traditional techniques and architectures as well as standard operation conditions. This becomes more urgent when recent proof-of-concept functional protein-based materials/components can replace rare earth and/or toxic components of our current technology without reducing performance. In this context, InOutBiolight aims at understanding the protein-polymer stabilization interaction, enhancing their mechanical, thermal, color-converting, and light-guiding features, and iii) advancing biohybrid lighting and photovoltaic technologies. The latter are placed at the forefront of the EU efforts for low-cost production and efficient consumption of electricity, a critical issue for a sustainable development of our society.