ALK-IN-21 (Compound B10), a potent ALK inhibitor for ALKG1202R mutation, exhibits remarkable enzymatic inhibitory potency with IC 50 values of 4.59 nM, 2.07 nM and 5.95 nM toward ALK WT , ALK L1196M and ALK G1202R , respectively. ALK-IN-21 efficiently inhibits the proliferation of ALK-positive Karpas299 and H2228 cells both with IC 50 values of 0.07 μM. ALK-IN-21 can be used for the research of anaplastic large cell lymphoma.