Overcoming　the　challenges　of　integrating　disparate　components　in　nanoarchitectures,　this　study　introduces　a　straightforward　strategy　based　on　a　mixed-valence　coordination　approach,　creating　an　ordered　ternary　heterostructure　integrated　with　ultrasmall　homojunction.　This　singular　ordered　homojunction-heterostructure　unites　ultrathin　1D　rutile　TiO2　nanowires　(NWs)　and　ultrathin　anatase　TiO2　NWs　with　0D　Prussian　Blue　Analogs　(PBAs)　nanoparticles　(NPs),　all　exhibiting　crystallographic　oriented　alignment　with　each　other,　forming　a　ternary　mesocrystals.　Experimental　and　theoretical　insights　disclose　that　the　complex　interplay　between　these　dissimilar　components　is　governed by　a　spontaneous　lattice　match　effect,　which　not　only　optimizes　but　also　directs　the　charge　transfer,　thereby　enhancing　both　efficiency　and　stability.　It　also　allows　for　tailoring　the　valence　states　of　Fe　within　the　PBA,　fine-tuning　of　the　composite＇s　photochromic　properties,　and　introducing　abundant　defect　structures　that　foster　strong　interaction　with　oxygen　molecules,　enabling　controllable　color-switching　dynamics.　Consequently,　the　FeII1−xFeIIIx-PBA/TiO2　exhibits　an　optimized　ternary　structure　of　R-TiO2/A-TiO2/PBA,　demonstrating　exceptional　photoelectronic　properties,　significantly enhancing　photochromism　and　secure　encryption　capabilities.　These　insights　establish　a　solid　foundation　for　engineering　sophisticated　complex-ordered　nanoarchitectures,　advancing　sustainable　energy　and　environmental　technologies.　©　2025　Wiley-VCH　GmbH.