Over the past few years, it has become clear that the mandatory reduction of energy consumption, the desire to rely less on fossil fuels and environmental pollution necessitate the development of sustainable and alternative energy sources. Technologies based on nanomaterials have proven to be promising in the field of renewable and sustainable energy in terms of optical and thermal properties, long-term stability and cost. However, it is essential to find suitable materials and then evaluate their performance by simulating them at the device level, offering a fast and inexpensive way to check device designs and processes. By exploiting first-principles simulation techniques from theoretical physics and chemistry, the TyLDE project aims to understand and rationalize the correlation between band topology and quantum confinement on their applications in the fields of photovoltaics (PV, direct conversion of energy between light and electricity) and thermoelectric (TE, direct conversion of energy between heat and electricity) in order to propose new interesting materials which will then be transferred to the level of device simulation. Our goal will be to exploit band topology and system dimensionality in order to: 1) simultaneously optimize electric and thermal conductivities in TE materials (leading to a boost in their performances way higher with respect the ones known at the present day); 2) engineer the size of excitons’ wave functions as well as their dispersions in PV systems, boosting exciton photogeneration of carriers and optimizing their diffusion. The success of this project will be a significant step forward in optimizing material properties for a new generation of devices for low power consumption and energy harvesting.