The direct production of branched semiconductor arrays with. highly ordered orientation has proven to -be a considerable challenge, over the last two decades. Here we report a mesoporous interfacial atomic rearrangement (MIAR) method to directly produce highly crystalline, finger-like branched Iron 'Oxide nanoarrays from the, mesoporous nanopyramids. This method has excellent versatility and flexibility for heteroatom doping of metallic elements, including Sri, Mn, Fe, Co, Ni, Cu, Zn,, and W, in which the mesoporous nanopyramids first absorb guest doping Molecules into the mesoporous channels and then convert the mesoporous pyramids, into branching artificial nanofingers. The crystalline structure can provide more optoelectronic active sites of the nanofingers by interfacial atomic rearrangements of doping molecules And mesopore Channels at the porous 'solid solid interface. As a proof-of-Concept, the:Sn-doped Fe2O3 artificial nanofingers;(ANFs) exhibit a high photocurrent density of similar to 1.26 mA/Cm-2, similar to 5.25-fold of the pristine rnesoporons Fe2O3 nanopyraniid arrayS furthermore; with surface Cheinicaliunctionalizatiori, the Sh-doped ANF.biOinterfaces allow rianomolar level recognition of metabolism related biomolecules (similar to 5 nm for glutathione). This MIAR method suggests -a new growth means of branched mesostructures, with enhanced optoelectronic applications.