Herein, we report a cross-linking method for the assembly of coiled-coil peptides into long fibers under mild conditions. This method is conducted with high specificity by intermolecular thioether bonds between site-directed incorporation of cysteine in the peptides and the benzylic bromide. By changing the bromomethyl group position, control of the polymerization efficiency could be achieved. This study provides a cost-effective strategy for intermolecular bonding, which may be further applied as a linkage to prepare functional nanomaterials.