DCLK1-IN-1 is a selective, in vivo-compatible chemical probe of the doublecortin like kinase 1 (DCLK1) domain that binds to DCLK1 and DCLK2 with IC50 of 9.5 nM and 31 nM, respectively. DCLK1-IN-1 inhibits DCLK1 and DCLK2 kinases with IC50 of 57.2 nM and 103 nM in kinase assay, respectively.