• A heterogeneous copper doped g-C 3 N 4 catalyst has been prepared. • An efficient approach for synthesis of 2-trifluoromethyl-benzimidazoles has been developed. • higher catalytic reactivity of the Cu/g-C 3 N 4 catalyst compared with homogeneous copper catalyst was observed. An efficient approach for the synthesis of 2-trifluoromethyl-benzimidazoles via cascade annulation of trifluoroacetimidoyl chlorides and amines using a heterogeneous copper doped g-C 3 N 4 catalyst has been developed. Compared with the previously reported homogeneous catalytic system, the reaction exhibits higher efficiency and the copper doped g-C 3 N 4 catalyst can be readily recycled for three times with slightly decreased catalytic reactivity. An efficient approach for synthesis of 2-trifluoromethyl-benzimidazoles through cascade annulation of trifluoroacetimidoyl chlorides and amines base on a heterogeneous Cu/g-C 3 N 4 catalyst has been reported. The protocol enables the formation of various 2-trifluoromethyl-benzimidazoles in up to 99% yield and the Cu/g-C 3 N 4 catalyst can be recycled for three times.