The invention comprises indole and indoline derivatives of the general formula &lt;FORM:0753919/IV(a)/1&gt; wherein R is hydrogen, methyl or ethyl, X1 and X2 are either a direct link together or each is a hydrogen atom, Y is a phenyl radical which may be substituted by halogen atoms, methyl, ethyl, methoxy or ethoxy radicals or a hydroxy group, or a phenyl radical substituted by a trimethylene or tetramethylene radical, or a naphthyl radical, Z1 is hydrogen, halogen, methyl, methoxy or hydroxyl and Z2 is hydrogen, halogen or methyl, and their preparation by two methods (1) heating a suitably substituted indole or indoline unsubstituted on the nitrogen atom with the hydrochloride of a 2-halogenmethyl imidazoline, preferably in the absence of solvents and with exclusion of atmospheric oxygen; and (2) reacting an N-alkali metal salt of a suitably substituted indole or indoline, which must not however contain free hydroxyl groups, with a 2-halogenmethyl imidazoline, advantageously in a benzene hydrocarbon solvent at reflux temperature.  The indole or indoline alkali metal salts are obtained by reacting the appropriate indole or indoline with a strongly alkaline agent such as sodamide, potassamide, lithium hydride or alkali metal.  In examples (1) 1-[imidazolinyl-(21)-methyl]-2-phenyl indole is prepared from sodium-2-phenyl indole and 2-chloro-methyl-imidazoline.  (2) 1 - [Imidazolinyl - (21) - methyl] - 2 - (411 - chlorophenyl) - 5 - chlorindole is prepared from 2-(41-chlorophenyl)-5-chlorindole and 2 - chloromethylimidazoline hydrochloride.  (3) 1 - [Imidazolinyl - (21) - methyl] - 2 - phenyl indoline and - 2 - (311 - methoxyphenyl)indoline are both prepared by the method of Example (2).  The latter compound is accompanied by the corresponding 311-hydroxyphenyl-indoline.  A list of further products is also given, together with a list of 2-aryl indoles suitable for use as starting materials.  The compounds of the invention form salts with organic and inorganic acids and the free bases or the salts may be made into therapeutic compositions with or without the addition of other sympathololytic or hypotensive agents.  2-Aryl indoles are prepared from the phenyl hydrazones obtained by the reaction of suitably substituted phenyl hydrazines with substituted or unsubstituted aryl-alkyl ketones, by heating said phenyl hydrazones with zinc chloride or with ether borofluoride in an inert solvent. 2-Aryl indolines are obtained by reduction, for example with zinc and hydrochloric acid, of 2-aryl indoles. 2-Halogenmethyl-4,5-imidazolines are obtained from halogen-aceto nitriles and ethylene diamine.ALSO:A therapeutic preparation is characterised by containing as an active ingredient a compound of the formula: &lt;FORM:0753919/VI/1&gt; wherein R is hydrogen, methyl or ethyl, X1 and X2 are either a direct link together or each is a hydrogen atom, Y is a phenyl radical which may be substituted by halogen atoms, methyl, ethyl, methoxy or ethoxy radicals or a hydroxyl group, or a phenyl radical substituted by a trimethylene or tetramethylene radical, or a naphthyl radical, Z1 is hydrogen, halogen, methyl, methoxy or hydroxyl and Z2 is hydrogen, halogen or methyl, or the salt of such a compound, with an organic or inorganic acid, with or without other sympathicolytic or hypotensive agents.  The compounds of the above general formula or their salts can be formed into tablets by combination with suitable carriers such as starch, lactose or talc.  Isotonic aqueous solutions of some of the salts can be made by the addition of sodium chloride if necessary.