In the Bi2O3–MO–P2O5 ternary system, the commonly observed sizable 1D ribbon-like units have been extended to their 2D infinite end member, leading to the novel tailormade Bi4MO4(PO4)2 compounds. It contains planar [Bi2O2]2+ derivatives, separated by two slabs of PO4, which create channels hosting the M2+ cations (M = Mg, Zn). For both compounds, supercell orderings occur comparatively to the predicted ideal crystal structure (VMg = 2Videal and VZn = 8Videal). In the Mg case a transition into the ideal lattice occurs above 450 °C. In spite of the conceptual assembly of 2D motifs, the final architecture is three-dimensional due to strong interbonds. Thus, our work gives new insights on the possibility for versatile organization of original secondary building units (SBUs) able to self-assemble into predicted structural edifices. Single-crystal and powder XRD versus temperature, high-temperature 31P NMR, as well as transmission electron microscopy were used for structural characterization. Preliminary electric characterization is also reported.