552,921. Cyano compounds. Cyanine dyes. Photographic sensitized emulsions. KODAK, Ltd. Aug. 14, 1941, No. 10350. Convention date, April 18. [Class 2 (iii)] [Also in Group XX] A dye base having the general formula shown in Fig. 1 or Fig. 2, where a and b are 0 or 1, m is o, 1, g or 3, n is 1 or 3, R is alkyl or aryl, R' and R<SP>11</SP> are alkyl, and Q and Z are the non-metallic atoms necessary to complete a 5- or 6-membered heterocyclic organic nucleus not containing another nitrogen atom, is prepared by condensing a 5- or 6-membered heterocyclic nitrogen base, not containing a second nuclear N atom but containing in the alpha or gamma position to the nitrogen atom a cyanomethyl group, with (Fig. 1) a cyclammonium quaternary salt containing in a reactive position a group which will condense with the methylene portion of the cyanomethyl group or with (Fig. 2) a p-dialkylaminobenzaldehyde or a p-dialkylaminocinnamaldehyde. The heterocyclic nitrogen base may be a quinoline or benzthiazole derivative, the cyclammonium quaternary salt a quinoline, benzthiazole, benzoxazole, thiazoline, or naphthathiazole derivative, and the group in a reactive position a halogen, a thioether, acylated arylaminovinyl, acylated arylamino-1:3-butadienyl, or acylated arylamino - 1:3:5 - hexatrienyl group. The condensation may be effected in the presence of a basic condensing agent such as pyridine and in a solvent such as an alcohol of the formula C n H 2n - 1 0H, where n is a positive integer, e.g. from 1 to 3. 2 - [cyano - (1 - ethyl - 4 - quinolylidene) - methyl] - quinoline is prepared by refluxing together 4-phenylmercaptoquinoline ethiodide, 2-quinolylacetonitrile, and triethylamine in absolute ethyl alcohol. Sodium hydroxide is added, the precipitate dissolved in hot ethyl alcohol, and the hydrochloride of the base precipitated by adding alcoholic hydrogen chloride. The base is obtained by dissolving the hydrochloride and triethylamine in absolute ethyl alcohol and pouring into water to precipitate the base. The base sensitizes a photographic silver halide emulsion..The hydrochloride is a non-sensitizer. 2-[cyano- (3 - ethyl - 2 - benzthiazolylidene) - methyl] - benzthiazole (sensitizer), 2 - [1 - cyano - - 3 - (1 - - ethyl - 4 - quinolylidene) - propenyl] - benzthiazole, (sensitizer), 2 - [1 - cyano - 3 - (3 - ethyl - 2 - benzoxazolylidene) - propenyl] - quinoline (very weak sensitizer), 2 - [1 - cyano - 3 - (3 - methyl - 2 - thiazolinylidene) - propenyl] - quinoline (very weak sensitizer), 2 - [1 - cyano - 3 - (3 - ethyl - 2 - benzthiazolylidene) - propenyl] - quinoline (weak sensitizer), 4 - [1 - cyano - 3 - (3 - ethyl - 2 - benzthiazolylidene) - propenylquinoline (strong sensitizer), 2 - [1 - cyano - 5 - (1 - - ethyl - 4 - quinolylidene) - 1:3 - pentadienyl] - benzthiazole (strong sensitizer), 2 - [1 - cyano - 5 - ( 1 - ethyl - 2 - quinolylidene) - 1:3 - pentadienyl] - benzthiazole (strong sensitizer), 4 - [1 - cyano - 5 - (3 - ethhl - 2 - benzthiazolylidene) - 1:3 - pentadienyl] - quinoline (weak sensitizer), 2 - [1 : cyano - 7 - (3 - ethyl - 2 - benzthiazolyli - dene) - 1:3:5 - heptatrienylbenzthiazole (strong sensitizer], 4 - [1 - cyano - 3 - (1 - ethyl - 4 - quinolylidene) - propenyl] - quinoline (weak sensitizer), 2 - [1 - cyano - 3 - (3 - ethyl -2 - benzthiazolylidene) - propenyl] - benzthiazole- (sensitizer), 2 - [1 - cyano - 5 - (3 - ethyl - 2 - benzthiazolylidene) - 1:3 - pentadienyl] - benzthia zole (fairly strong sensitizer), 2 - [1 - cyano - 5 - (1 - - ethyl - 2 - # - naphthathiazolylidene) - 1:3 - pentadienyl] - benzthiazole (fairly strong sensitizer), and 2 - [1 - cyano - 3 - (3<SP>1</SP> - phenyl - 2<SP>1</SP> - benzthiazolylidene) - propenyl] - benzthiazole are similarly prepared. 4 - [1 - cyano - (p - dimethylamino) - styryl] - quinoline is prepared by refluxing together 4 - quinolylacetonitrile, p - dimethylamino - benzaldehyde, and acetic anhydride. The base is a weak sensitizer. 2 - (1 - cyano - 4 (p - dimethylamino) - 1:3 - butadienyl) - benzthiazole is prepared by refluxing together 2-benzthiazolylacetonitrile, p-dimethylaminocinnamaldehyde, piperidine, and absolute ethyl alcohol. The base is a very weak sensitizer. Cyano cyanine and like methine dyes may be prepared by reacting the cyano cyanine bases, cyano styryl bases, and cyano cinnamyl bases with alkyl esters. 10 - cyano - 3 ethyl - 1 - methylthia - 4<SP>1</SP> - carbocyanine bromide (weak sensitizer) is prepared by heating together 4-[1-cyano-3- (3 - ethyl - 2 - benzthiazolylidene) - propenyl] - quinoline and methyl p-toluenesulphonate, and adding potassium bromide to the methyl alcoholic solution. 10 - cyano - 3:3<SP>1</SP> - diethylthiacarboellanine iodide is prepared by heating together 2-[1- cyano - 3 - (3 - ethyl - 2 - benzthiazolylidene) - propenyl] - benzthiazole and diethyl sulphate, and adding methyl alcoholic sodium iodide to the methyl alcoholic solution. The dye bases and dyes may be incorporated in washed finished photographic silver halide emulsions, or plates or films may be bathed in a solution thereof. Specifications 551,824 and 552,922, are referred to. The Specification as open to inspection under Sect. 91 comprises also the preparation of dye bases of the formulae shown in Fig. 1 (Cancelled) and Fig. 2 (Cancelled), wherein a and b represent 0 or 1, m represents a positive integer of from 1 to 4, n represents 1 or 3, D represents an arylene group, R represents an alkyl or aryl radical, R<SP>1</SP> and R" represent alkyl radicals, and Q and Z represent the non-metallic atoms necessary to complete a heterocyclic organic nucleus. This subject-matter does not appear in the Specification as accepted.