hCAIX-IN-12 is a potent hCAIX inhibitor with IC 50 values of 0.74, 10.78 μM for CAIX and CAII, respectively. hCAIX-IN-12 shows antiproliferative effect and induces apoptosis. hCAIX-IN-12 increases ROS production. hCAIX-IN-12 has the potential for the research of colorectal cancer (CRC).