NOVELTY - Preparing acrivastine, comprises: (a) hydrolyzing ester group of ethyl (E)-3-(6-(1-(4-tolyl)-1-hydroxy-3-pyrrolidino-propyl)-2-pyridyl)-acrylate (I) with base and acidifying to give (E)-3-(6-(1-(4-tolyl)-1-hydroxy-3-pyrrolidino-propyl)-2-pyridyl)-acrylic acid (II); (b) dehydrating (II) by sulfuric acid, neutralizing with base and extracting aqueous layer, removing solvent by distillation and crystallizing the product to give acrivastine as a mixture of (E,E-isomer)/(E,Z-isomer); and (c) purifying the E,E-isomer/E,Z-isomer mixture to give pure acrivastine as E,E-isomer.    USE - The process is useful for preparing acrivastine (claimed), which is useful for treating chronic urticaria, allergic rhinitis and hay fever. No biological data given.    ADVANTAGE - The process: is continuous and reduces the time period for reaction workup and increases the feasibility on the plant scale; and can be performed utilizing non-toxic and environmental friendly conditions, hence it is safe, economical and environmentally friendly and feasible at commercial scale.    DETAILED DESCRIPTION - Preparing acrivastine, comprises: (a) hydrolyzing ester group of ethyl (E)-3-(6-(1-(4-tolyl)-1-hydroxy-3-pyrrolidino-propyl)-2-pyridyl)-acrylate (I) with a base and subsequently acidifying to give (E)-3-(6-(1-(4-tolyl)-1-hydroxy-3-pyrrolidino-propyl)-2-pyridyl)-acrylic acid (II); (b) dehydrating (II) by sulfuric acid, neutralizing with base, and extracting aqueous layer using solvent(s), followed by removal of solvent by distillation and crystallizing the product using solvent(s) to give acrivastine as a mixture of (E,E-isomer)/(E,Z-isomer); and purifying the mixture of E,E-isomer/E,Z-isomer by using solvents or mixture of solvents to give pure acrivastine as E,E-isomer. INDEPENDENT CLAIMS are also included for:    (1) synthesis of acrivastine, comprising (a1) dehydrating (I) using sulfuric acid, followed by heating the reaction mass in alcoholic solvent, neutralizing with base, and extraction from aqueous layer using suitable solvent(s) followed by removal of solvent by distillation and crystallization of the product by using solvent(s) to give ethyl (E)-3-(6-(3-pyrrolidino-1-(4-tolyl)-prop-1E,Z-enyl)-2-pyridyl)-acrylate (III) as a mixture of (E,E-isomer)/(E,Z-isomer), (b1) purifying the mixture of (III) as a mixture of E,E-isomer/E,Z-isomer by using suitable solvents or mixture of solvents to get pure (III) as pure E,E-isomer, and (c1) hydrolyzing ester group of (III) with a suitable base, and acidifying the reaction mixture to get acrivastine as pure E,E-isomer;    (2) polymorph Form-A of acrivastine having X-ray powder diffractogram (XRPD) peaks as given in the specification;    (3) polymorph Form-B of acrivastine having an XRPD peaks as given in the specification;    (4) preparing polymorphic form-A of acrivastine comprising crystallizing acrivastine in a suitable solvent comprising esters; and    (5) preparing polymorphic form-B of acrivastine comprising crystallizing acrivastine in a suitable solvent comprising (1-6C) alcohols.