hCAIX-IN-12 is an effective hCAIX inhibitor, IC50 for CAIX and CAII is 0.74 and 10.78 µM , respectively. hCAIX-IN-12 inhibits cell proliferation and induces apoptosis. HCAIX-IN-12 can increase the generation of ROS. HCAIX-IN-12 has research potential in colorectal cancer (CRC).