Multiple RNA decapping enzymes coexist in mammalian cells to regulate decay of partially overlapping sets of cellular transcripts, but a comprehensive understanding of cellular substrate selectivity of each enzyme is yet to be achieved. Previously we demonstrate the utility of TimeLapse-seq in global profiling of RNA stability changes in human Dcp2 knockout cells. However, secondary transcriptional changes and upregulation of alternative decay pathways have obscured complete mapping of Dcp2 substrates. Here, we present the discovery and first application of a cell-permeable, highly selective Dcp2 ligand in the chemical genetic study of its RNA substrates. Overall design: RNA isolated from cells pre-treated with respective compounds +/- 2 h s4U feed was subjected to oxidative-nucleophilic-aromatic-substitution chemistry and sequenced. All sequencing for experimental samples was performed in duplicate per condition assessed, while negative controls were performed as single replicates without s4U treatment.