Propylene production is classified as the 4th largest emitter of greenhouse gases among the major chemical compounds. As the polypropylene market is huge and still growing, it is essential to find alternatives to current, energy-intensive production processes to meet the European environmental challenges. Other C3 derivatives, more specifically propanol and propanal, are also very high added-value chemicals with growing markets, obtained via waste-generating and energy-consuming processes. Today, unused carbon resources are widely available and most of the time wasted.The C123 project’s main goal is the validation in a relevant environment (TRL5) of an efficient and selective transformation of current generally accessible, unexploited, cheap methane resources (stranded gas (CH4) and biogas (CH4+CO2)) to propylene in particular and C3 products in general. To this aim, C123 will develop new catalytic materials in novel process configurations and related operating procedures allowing the conversion of these resources to propylene through Oxidative Conversion of Methane, leading to an ethylene, carbon monoxide, and hydrogen mixture with an optimised composition for further HydroFormylation into propanal and/or propanol, ultimately being dehydrated into propylene, either in an integrated manner or as a stand-alone step. C123 will adopt an integrated approach, not studying each step separately but considering the process as a whole, optimising recycling, avoiding separation, using variable feedstocks, and increasing resource and carbon efficiency. The process will be evaluated and validated for implementation both as decentralised localised units (~10 kt/y) – the modular route, and in existing large facilities (>140 kt/y) –the add-on route. Throughout the development and thanks to the perfect complementarity of the partners and the very strong industrial commitment, emphasis will be put to maximise further exploitation of the results through industrial implementation.