The　donor-acceptor　(D-A)　hybrid　crystals　are　an　emerging　class　of　crystalline　hybrid　complexes　composed　of　semi-conductive　organic　and　inorganic　components　at　the　molecular　level.　These　unique　crystals　not　only　possess　intrinsic　electron-transfer　photochromic　properties　upon　the　high-energy　irradiations　but　possibly　exhibit　unusual　room-temperature　phosphorescence　(RTP)　emissions　when　suitable　charge-transfer　states　formed　with　the　low-energy　irradiations.　Herein,　we　reported　that　an　interesting　class　of　D-A　hybrid　crystals　indeed　exhibited　two　such　properties　in　which　two　D-A　components,　polyoxometalates　(POMs)　and　naphthalene　diimides　(NDIs),　are　intercontacted　through　uncommon　anion-pi　interactions.　To　go　deep　into　their　structure-property　relationships,　five　D-A　hybrid　crystals　with　different　POMs　(PW12O403-,　SiW12O404-or　Mo6O192-)　and　protonated　(or　zinc-coordinated)　pyrazolyl-substituted　NDIs　have　been　synthesized.　Their　light-induced　color　changes　and　RTP　properties　have　been　systematically　investigated,　which　revealed　that　the　matching　electron　energy　levels　of　POMs　and　NDIs　are　the　first　factor　to　decide　their　RTP　emissions　while　the　heavy　atoms　in　both　POMs　and　coordination　metal　cations　are　mainly　beneficial　to　their　quantum　yields.　Notably,　the　RTP　quantum　yields　for　these　interesting　photochromic　D-A　hybrid　crystals　are　up　to　5.9%.