Aside from specialized design artifacts solving 'wicked' problems in a distinct organizational context, prescriptive (design) theories for solving classes of problems are well-accepted results of design science research. Especially for intricate problem fields, as IT service management or EA management, the development of such theories remains a highly complex research endeavor spanning a longer period of time. In this paper, we discuss how patterns, i.e. practice-proven, re-usable solutions to recurring problems, can be used to ease the establishment of a design theory, and to provide practice-relevant intermediary results prior to theory completion.