Swedish Co-educational School is one of the Finnish pioneers in co-eduction. The school was established in 1888 and was the first Swedish co-educational school outside the capital city. The school operated in the corner of the streets Kristiinankatu and Eerikinkatu until 1894 when it moved to a building situated on the corner of the street Linnankatu and Brahenkatu. In the early years of the 1900s, the school board started planning a schoolhouse. A plot for the new schoolhouse was purchased from the corner of the Puolalanpuisto park. Architect Wivi Lönn, one of the first female architects in Finland and established school architect designed the building. The Art-Nouveau schoolhouse was completed in 1910.

The building is situated in the south-east corner of the park, on a plot that is in the slope descending south. On the northern street façade, the building has three storeys and on the southern yard façade four storeys. The ground floor is made of grey granite stone on the street side, a typical solution for Art-Nouveau buildings. The main façade material is yellow-painted plaster. The red-brick mansard roof is a central feature in the building.