Adequate interior lighting is still a huge challenge for architects around the world The light falls into the building, still not reaching its potential..A SUN CATCHER was created in response to real problems. The world is getting more and more urbanized and denser, urban interiors are becoming tighter and under-lighted. The described device is a way to take possibly all light that falls on a building at a given moment. It gathers the light when it does not fall (or almost doesn’t fall) into the room. What is more it can scatter the light, to create a comfortable, cosy space, instead of focused at one point, sharp light. In urban interiors we will see balconies, windows, loggias. Man creates intermediate forms to satisfy his needs. He wants space, which is given to him by being outside of the concrete frames of buildings. A simple form of a cuboid with a steel body and glass partitions maximizes the amount of light in the interior and gives it back to urban interiors at night. The boxes formed on the facades will create various proposals in urban interiors, solving the problem of balcony aesthetics, the lack of light during the day and the failure to use its energy potential at dusk when it starts to be missing. The research carried out shows clearly the difference between using the Sun Catcher and not using it. The device clearly scatters the sun's rays, illuminating almost evenly throughout its space without creating a focused, sharp light, as in the case of an interior illuminated without using the Sun Catcher. The device works both day and night and has different possibilities to adapt it to space. On sunny days the box performs its main function - it illuminates the interior, the receiver in the apartment has much more light than from the window. The box absorbs most of the heat, which partially solves the problem of overheating of the building partitions. Sun Catcher collects all possible light, disperses it, smoothes and distributes it to the whole interior. Using only the window shows that rays parallel to the fasade will never reach the inside, and those that go at a greater angle will hit the window to an unsatisfactory extent in terms of light. The use of the Sun Catcher will ensure that any light that is on the corresponding facade will be fully collected, redirected to the interior and more dispersed than before. At the same time, the light and heat comfort in the apartment is increased. On days less abundant in sunlight, the box will serve as an additional living space. Extremely wide range of use is limited only by the user's imagination. At night, the Sun Catcher turns into a Light Thrower to light up streets and courtyards using modern quantum dot technology. Invisible dots will draw some energy and give it back after dark. In addition, the structure of the glass baffle will stop most of the harmful UV and IR radiation and let the visible light through. All this happens thanks to the special structure of the glass partition. Two panes of glass has in between each other a layer of nanoparticles surrounded by conductors and electric charge conveyors. Using different sizes of dots, it is possible to obtain any colour of light and dissipate accumulated electrical energy. The Sun Catcher's action leads the user outside the walls of the apartment, helping to make social contacts between neighbours. As recent months have shown, additional space is as valuable as sunlight. The balcony substitute is becoming very important in the life of both the resident and the entire neighbourhood community. Sun Catcher accumulated as much as balconies would bring a social aspect to the use of the device. A street full of cuboidal lanterns would undoubtedly make current interiors more attractive. Moreover it would increase the safety and atmosphere perceived by the space user. The Sun Catcher is a device designed for existing and future buildings. It is universal in its simplicity and using all possible spectrum of light potential.