Favipiravir was chosen as a model for study on cocrystal screening of nucleoside analog. Seven coformer candidates were selected according to supramolecular synthon method and verified with molecular modeling and hot-stage. Only 4-amino benzoic acid was able to form cocrystal with the color transformation from white to yellow. Fluorescence study was investigated and compared during cocrystallization. Due to the fluorescent emission nature of nitrogen heterocyclic nucleoside analog, fluorescence could also be utilized as a promising tool in screening cocrystals. This study provides an efficient pathway toward nucleoside analog cocrystal and affords a fluorescent screening method for drug cocrystal research.