Perovskite　materials　have　exhibited　promising　potential　for　universal　applications　including　backlighting,　color　conversion,　and　anticounterfeiting　labels　fabricated　using　solution　processes.　However,　owing　to　the　tendency　of　those　materials　to　have　uncontrollable　morphologies　and　to　form　large　crystals,　they　cannot　be　utilized　in　discontinuous　microminiaturization,　which　is　crucial　for　practical　optoelectronic　applications.　In　this　research,　combining　the　effects　of　adding　polyvinylpyrrolidone　(PVP),　precisely　controlling　the　inkjet　printing　technique,　and　using　a　postprocessing　procedure,　we　were　able　to　fabricate　in　situ　crystallized　perovskite-PVP　nanocomposite　microarrays　with　perfect　morphologies.　The　viscosity　of　the　perovskite　precursor　increased　with　the　addition　of　PVP,　eliminating　the　outward　capillary　flow　that　induces　the　coffee-ring　effect.　In　addition,　because　of　the　presence　of　metallic　bonds　with　the　Câ•O　groups　in　PVP　and　the　spatial　confinement　of　such　a　polymer,　we　were　able　to　fabricate　regulated　CsPbBr3　nanocrystals　capped　with　PVP　and　with　a　uniform　size　distribution.　The　as-printed　patterns　showed　excellent　homogeneity　on　a　macroscale　and　high　reproducibility　on　a　microscale;　furthermore,　those　patterns　were　invisible　in　the　ambient　environment,　compatible　with　flexible　substrates,　and　cost-efficient　to　produce,　indicating　that　this　technique　holds　promising　potential　for　applications　such　as　anticounterfeiting　labels.　©　2019　American　Chemical　Society.