Photochromic　materials　and　room-temperature　phosphorescence　(RTP)　are　essential　for　applications　in　optoelectronics　and　bioimaging.　Organic-inorganic　hybrid　materials,　particularly　those　exhibiting　donor-acceptor　(D-A)　characteristics　through　supramolecular　interactions,　have　shown　significant　potential　to　integrate　both　photochromic　and　RTP　properties.　Among　them,　the　anion-π　and　π-π　interactions　have　been　extensively　studied;　however,　the　role　of　anion-π-π　interactions　in　hybrid　materials　remains　largely　unexplored.　This　study　investigated　three　naphthalenediimide-polyoxometalate　(NDI-POM)　hybrids:　(H2DMAP-NDI)·(HPW12O40)·(NMP)2　(1),　(HDMAP-NDI)2·(HPW12O40)·(NMP)2　(2),　and　(HDMAP-NDI)2·(HPW12O40)·(NMP)7　(3),　focusing　on　the　impact　of　anion-π-π　interactions　on　their　photochromic　and　RTP　properties.　The　results　indicate　that　hybrid　1　exhibits　the　fastest　photoresponse　and　highest　RTP　quantum　yield,　primarily　driven　by　anion-π　interactions.　Hybrid　2,　which　involves　anion-π-π　interactions,　shows　slower　photochromism　and　lower　RTP　yield　due　to　exciton　localization　and　nonradiative　decay　paths　resulting　from　π-π　stacking.　Hybrid　3,　characterized　by　excessively　strong　interactions,　is　unstable　and　nonemissive.　This　study　provides　valuable　insights　into　the　role　of　anion-π-π　interactions　in　hybrid　materials　and　offers　a　framework　for　designing　advanced　photoresponsive　materials　with　tunable　properties　for　diverse　applications.　©　2025　American　Chemical　Society.