Abstract: By using Cp*Co(Ⅲ)I₂(CO) as the catalyst with methyl 1-(pyrimidin-2-yl)-1H-indole-6-carboxylate and phenylacetylene as the raw materials, an indole-skeleton fluorescent molecule with 91% yield was efficiently synthesized by Co-catalyzed C—H alkenylation at room temperature. The primary properties of the fluorescent molecule were investigated, and the compound showed good fluorescence properties with large Stokes shift. The preparation by C—H functionalization shortened reaction routes and improved atom-economy as well as step-economy, which empowered it to be utilized as fluorescent dyes.