The new PETRA III facility at DESY is currently coming to life. First undulator beamlines at PETRA III are already in user operation and others are in their final construction phase. Once all new beamlines are operating in full user mode, it is planned to shut down DORIS III by the end of 2012. This shutdown will discontinue a number of very successful beamlines and instruments, which serve techniques not currently implemented at PETRA III. In order to carry on these activities in the future and to provide competitive beamlines and instrumentation for techniques not requiring ultimate brilliance, DESY plans to build additional beamlines at PETRA III. One of these will focus on activities currently being performed at single/powder diffraction beamlines like D3, F1, BW1 (and B2). The research areas at these beamlines range from chemical crystallography over materials and earth scienes till life sciences. Typical applications cover diffuse scattering studies, charge density analysis, phase transitions, also under external fields, disordered and modulated structures and topography studies all at ambient and non-ambient conditions (low/high temperature, high pressure). The workshop aims at discussing the concept of the beamline with its potential users. Topics will include energy range and resolution, beam size, beam otics as well as special sample environments and whatever is considered as important by the potential user community. As a final result of the workshop a concept and scientific case for insuring future long term funding of the new beamline should be formulated.