The invention comprises compounds of the formula <;FORM:0774780/IV(b)/1>; or of the formula <;FORM:0774780/IV(b)/2>; wherein R is an alkyl, substituted alkyl, aralkyl or alkenyl group, R1 is a phenanthryl, naphthyl or a 2-thienyl group, R2 is a hydrogen atom or a methyl group, R3 is a hydrogen atom or an alkyl, substituted alkyl, aralkyl, phenyl or substituted phenyl or furyl group, X is an anion and Z represents the non-metallic atoms to complete a heterocylic nucleus of the thiazole, benzthiazole, naphthathiazole benzoxazole, naphthoxazole, benzselenazole napthaselenazole or thiazoline series, which nuclei may be substituted, e.g. by alkyl, aryl, thienyl, halogen, hydroxy or alkoxy atoms or groups ; it also comprises the process for the preparation of the above compounds and also the broader class of compounds of the formula I wherein R1 may be any carbocyclic aromatic group or thienyl group, wherein a compound of the formula <;FORM:0774780/IV(b)/3>; is condensed with a ketone of the formula or <;FORM:0774780/IV(b)/4>; The quaternary salt of the formula III may be formed in situ by using the free base together with a compound of the formula R-X. In the above general formul R may suitably be a saturated alkyl group of 1-4 carbon atoms or a b -hydroxyethyl, carboxymethyl, carbethoxymethyl, methoxyethyl, benzyl or allyl group ; X may suitably be a chloride, bromide, iodide, perchlorate, thiocyanate, acetate, methylsulphate, ethylsulphate, benzenesulphonate or toluenesulphonate anion ; Z may suitably be the atoms necessary to complete a thiazole, benzthiazole, naphthathiazole, benzoxazole, naphthoxazole, benzselenazole, naphthaselenazole or thiazoline ring which may be substituted for example by methyl, phenyl, chlorine, bromine, iodine, methoxy, hydroxy, methylenedioxy or ethoxy atoms or groups ; R1 may suitably be a phenyl, tolyl, chlorophenyl, hydroxyphenyl, methoxyphenyl, naphthyl, di-methylphenyl, p - dimethylaminophenyl, p - diethylaminophenyl, 9 - phenanthryl or 2 - thienyl group and R3 may suitably be a saturated alkyl group of 1-4 carbon atoms or a benzyl, phenyl, tolyl, b -methoxyphenyl or furyl group. Suitable ketones of the formul IV and V are 1-acetonaphthone, acetophenone, isophorone, methyl - 2 - thienylketone, p - dimethylamino-acetophenone, 9 - acetylphenanthnene, 3 : 5 - dimethyl - 2 - cyclohexene - 1 - one, 5 - ethyl - 3 - methyl - 2 - cyclohexene - 1 - one, 5 - furyl 3 - methyl - 2 - cyclohexene - 1 - one and 3 - methyl - 5 - phenyl - 2 - cyclohexene - 1 - one. In examples there are prepared by the above process, (1) 3 - ethyl - 2 - (2 - a - naphthylpropenyl) benzthiazolium iodide ; (2) 3-ethyl-2 - (2 - phenyl)propenyl - benzthiazolium - p - toluene sulphonate ; (3) 3 - ethyl - 2 - (1 : 5 : 5-trimethyl - 3 - cyclohexenylidene) methylbenzthiazolium iodide ; (4) 3 - ethyl - 2 - (2 - (2 - thienyl) propenyl) benzthiazolium p - toluene-sulphonate ; (5) 1-ethyl-2-(2-(2-thienyl) propenyl) naphtha [1 : 2] - thiazolium iodide ; (6) 3 - ethyl - 2 - (2 - (p - dimethylaminophenyl) propenyl) benzthiazolium iodide ; (7) 3 - ethyl-2 - [2 - (2 : 5 - dimethylphenyl) propenyl) benzthiazolium iodide ; (8) 3 - ethyl - 2 - (2 - (9 - phenanthryl) propenyl) benzthiazolium iodide ; (9) 1 - ethyl - 2 - (2 - p - hydroxyphenyl) propenyl - naphtha [1 : 2] - thiazolium iodide ; (10) 1 - methyl - 2 - (2 - (1 - naphthyl) propenyl) naphtha [1 : 2] - thiazolium iodide ; (11) 5 - chloro - 3 - ethyl - 2 - (1 : 5 : 5 - trimethyl - 3 - cyclohexenylidene) - methylbenzthiazolium p - toluene sulphonate ; (12) 3-ethyl-2-(1 : 5 : 5-trimethyl - 3 - cyclohexenylidene) - methylbenzoxazolium iodide ; (13) 3-ethyl-2-(1 : 5 : 5-trimethyl - 3 - cyclohexenylidene) methyl benzselenazolium iodide ; (14) 2-(1 : 5-dimethyl-3-cyclohexenylidene) methyl - 3 - ethyl - benzthiazolium iodide ; (15) 1-ethyl-2-(1 : 5 : 5-trimethyl - 3 - cyclohexenylidene) methyl naphtha [1 : 2] - thiazolium iodide and (16) 3-ethyl - 2 - (1 : 5 : 5 - trimethylcyclohexenylidene) methylnaphtha : [2 : 1] - thiazolium iodide. Specifications 344,409 [Group IV], 637,039, 669,174 and 774,779 [all in Group IV (c), are referred to.;FORM:0774780/IV(b)/4>;FORM:0774780/IV(b)/3>;FORM:0774780/IV(b)/2>;FORM:0774780/IV(b)/1>