Trisindolylmethanes (TIMs) exist in many bioactive natural products and are frequently applied in medicinal chemistry and materials science. Herein, a simple and efficient protocol promoted by B(C6F5)3·H2O for the synthesis of their fluoroalkylated analogues, fluoroalkylated 3,3',3''-TIMs, is reported for the first time. Easily accessible fluorocarboxylic acids are utilized as the fluoroalkyl sources, exhibiting an obvious fluorine effect. This convenient and green process features mild and metal-free conditions, easy scale-up, and an environmentally friendly byproduct.