Abstract Tantalum (or niobium)-alkyne complexes are produced by treatment of acetylenes with the low-valent tantalum (niobium) derived by zinc reduction of TaCl 5 (NbCl 5). Substituted 1-naphthols are prepared regioselectively by reaction of o-phthalaldehyde with the tantalum (or niobium)-alkyne complexes in good to excellent yields.