Size-controlled micro- and nanocrystals of a [Ru(bpy)3][NaCr(ox)3] coordination network are prepared using reverse micelles. Compared with the bulk reference, the 2E emission of the Cr(III) ions indicates an efficient directional energy migration toward the surface of the nanocrystals.

Chromium(III)-trisoxalate,[Cr(ox)₃]^3- (ox = C₂O₄^2-), incorporated into polymeric networks of composition [NaCr(ox)₃][M^II(bpy)₃] and [NaCr(ox)₃][M^III(bpy)₃]ClO₄ (bpy= 2,2'-bipyridine, M^{II =} Zn, Fe, Ru; M^{III =} Rh, Cr), results in interesting features ranging from phonon-assisted and resonant energy migration within the R1 line the ²E state to persistent spectral side-hole burning via the latter, and manifestations of specific nearest-neighbour π–π interactions between bipyridine and oxalate.