With an aim to develop a public theology for an age of information media (or media theology), this article proposes a new God-concept: God is a communicative system sui generis that autopoietically processes meaning/information in the supratemporal realm via perfect divine media ad intra (Word/Spirit). For this task, Niklas Luhmann's systems theory is critically appropriated in dialogue with theology. First, my working postmetaphysical/epistemological stance is articulated as realistic operational constructivism and functionalism. Second, a series of arguments are advanced to substantiate (...) the thesis: (1) God is an observing system sui generis ; (2) self-referential communication is divine operation; (3) unsurpassable complexity is divine mystery; (4) supratemporal autopoiesis of meaning is divine processing; (5) agape is the symbolic medium of divine communication. Third, this communicative model of God is developed into a trinitarian theology, with a claim that this model offers a viable alternative beyond the standard (psychic, social, process) models. Finally, some implications of this model are explored for constructive theology (conceiving creation as divine mediatization) and for science-and-religion in terms of derivative models: (1) God as a living system sui generis and (2) God as a meaning system sui generis. (shrink)