Architectural-urban task of a business building project in addition to urban and design consists of a technical part. The technical part of the task includes the detailed design and parts with the elaboration of the construction and installation of the office building. Through the first part of the task, we get acquainted with the location, analyze its position and location in the city, and re-examine the historical origin of the existing post-urban zone. In the second part of the task, we deal with the design of urbanism. The existing advantages are being exploited, and the disadvantages are being addressed by urban interventions in the area. The diagonal which represents the main direction of the fluid movement of people is opposed by the solid and static diagonal of the constructed. The vision of the future plays an important role in the design but the improvement of the existing situation and the contribution to the community and the city remains the main goal. The social facilities on the ground floor are designed for various groups of users from the surrounding area. The third part of the task refers to the design of one of the buildings from the plot designed in the last part. In this final work, the default building is located on the very north of the plot. Drawn into the plot it faces Kneza Trpimira Street in the east, Gacka Street in the north, and with its western and southern facades, it opens towards the urbanism of the plot. This diversity of the façade is reflected in the functional design of the floor plan. The building remains true to the idea of a solid and static diagonal it forms but on the ground floor, it leaves a space of fluid movement thus, attaching it to urbanism. After designing the building we approach the technical part of the task. It includes the characteristic details for the detailed design, construction of the building, and installation. The importance of ecology was taken into account when designing the installations. Thus, solar panels are designed on the roof, and rainwater from the roof is used to water the plants in the interior and exterior.