A　detailed　study　of　topological　phase　transition　is　essential　for　guiding　the　controlled　synthesis　of　materials.　Herein,　a　series　of　zeolitic-imidazolate　frameworks　(ZIFs)　and　their　derived　metal　oxides　with　tailored　morphologies　and　adjustable　phases　from　ZIF-L　to　ZIF-8　to　ZnO　were　reported.　More　significantly,　the　phase　transformation　and　morphology　control　of　the　product　could　be　achieved　by　simply　changing　the　molar/volume　ratio　of　the　reagents　without　adding　any　surfactant,　and　the　growth　mechanism　was　systemically　investigated.　Benefiting　from　their　unique　structural　advantage,　when　fabricating　gas　sensors,　all　of　the　products　and　their　derivatives　exhibited　excellent　gas-sensing　selectivity　and　rapid　response/recovery　times　toward　acetone　vapor.　In　addition,　the　gas-sensing　mechanism　and　the　causes　for　the　gas-sensing　performance　discrepancy　in　different　sensors　were　also　studied.　The　results　showed　that　the　oxygen　vacancy　(O-V)　content,　structures,　and　morphologies　of　the　product　were　closely　related　to　their　comparable　sensitivities.　The　phase　transition　and　morphology　evolution　of　ZIFs　and　ZnO　in　this　study　might　bring　a　deep　understanding　of　the　metal-organic　framework　crystallization　process,　which　is　expected　to　help　the　development　of　more　precise　control　strategies　for　MOF-based　materials　with　customized　functional　properties.