Indium(III) chloride enabled the efficient synthesis of δ-lactams via intramolecular cyclization of ynamido-tethered conjugated styryl-ynes. In this process, formation of the δ-lactams from easily available ynamido-tethered conjugated styryl-ynes does not requiring an additional oxidant (N-oxides, sulfoxides, or epoxides). The reaction requires only 3.3 equivalent InCl3 at 40 ℃ in minutes under mild reaction conditions to afford δ-lactams. Keywords: Indium(III) chloride、δ-lactams、intramolecular cyclization.