T025 is a pan CLK inhibitor with Kds of 4.8, 0.096, 6.5, 0.61, and 0.074 nM for CLK1-4, respectively. T025 displays anti-proliferative activities with IC50s of 30-300 nM in hematological and solid cancer cell lines. T025 can be used in studies about MYC-driven diseases.