A photographically useful alkynyl compound is disclosed which is nonionic under aqueous alkaline photographic processing conditions. The alkynyl compound is comprised of an alkynyl group attached to a methylene group through a divalent chalcogen or an imino group. The methylene group is activated by an electron withdrawing substituent. The alkynyl compounds are useful in direct positive internal latent image forming emulsions as nucleating agents and in negative working surface latent image emulsions to increase speed and/or contrast.