Among photovoltaic technologies, Dye-Sensitized Solar Cells (DSSC) are hybrid solar cells that contain a wide band-gap metal oxide semi-conductor usually photosensitized by an organic dye. In the last years, their power conversion efficiency has overcome 14% and they have demonstrated their capacity to perform under low-light environments. Besides their lifetime is demonstrated over 10 years. 1 DSSCs can be can semi-transparent and colourful which makes them interesting for use as windows or light-shading systems. 1-2 Unfortunately, when developing semi-transparent DSSCs, a trade-off has always to be found between transparency and efficiency. The colour and level of transparency are fixed during the fabrication process and they mainly rely on the choice of the photosensitizer and the thickness of the metal oxide mesoporous layer. For the massive integration of DSSCs in buildings as windows, DSSCs showing variable and self-adaptable transparency with the daylight intensity would be very valuable. To tackle this challenge, we recently proposed a new approach based on the development of photochromic sensitizers. In this communication, we will present our strategy to design dyes reconciling photochromism and photovoltaic properties. We will discuss the structureproperties relationships of these photochromic molecules and we will show how they can be employed to develop a new generation of functional solar cells capable to change their colour, self-adjust their transparency and their photovoltaic energy conversion depending on the intensity of the daylight. 3 We will also discuss the factors influencing the photochromic behaviour and the photovoltaic properties of this new class of dyes in devices. 4