This area is the only quarter that is still available for an inner city expansion. The structure of the area is characterized by underutilized properties with commercial use, large-scale retail businesses, commercial sectors and isolated residential areas in the middle of the mixed location. In order to promote orderly urban development and enhance the district as a whole, the state capital of Wiesbaden adopted the "Mainzer Straße" urban development master plan in 2007 with the following overall objectives:

• Spatial and functional connection to the city center
• Realization of a compatible mix of residential and commercial uses
• Design definition of the city center
• Construction of manageable spatial units as building blocks with a high proportion of green space
• Architectural and design enhancement of Mainzer Strasse as the southern entrance to the city center
• Expansion of the transport infrastructure

The planning for the entire area of around 150 hectares has now been divided into different areas so that the development of individual building plans can be specified in line with the respective urban development requirements. The "Area A" became legally binding on August 26, 1998 and the "Area E" with the central administrative and judicial location on March 8, 2005.

The "Mainzer Straße Area D - south of Welfenstraße" development plan came into force on December 15, 2010 and the "Mainzer Straße Area C - south of Siegfriedring" development plan came into force on July 26, 2022. The development plans for the other areas are at various stages of planning and are the subject of consultations by the municipal committees. The realization of the urban development concept for all areas is an ongoing process that began in 1992 with the first major construction projects and is expected to take a medium to long-term time horizon until the complete transformation.

The "Mainzer Strasse" urban development master plan was adopted by the Wiesbaden City Council on June 28, 2007 with resolution number 0036.