object of the present invention can be easily performed and it allows to obtain pyridinylidene phthalides of formula i with good yields without using the aforesaid phosphonium salt xi the process object of the present invention provides for the reaction between a compound of formula ii and a compound of formula iii the compounds of formula ii are known and easily obtainable for instance according to the synthetic route described in j chem soc 1929 200 in the compounds of formula ii the groups r and r 1 have the above reported meanings particularly preferred compounds of formula ii are those wherein at least one between r and r 1 represents or 2 even more preferred those wherein one or both between r and r 1 are och 3 also the starting compounds of formula iii are generally known commercially available or obtainable according to processes reported in the literature particularly preferred compounds of formula iii are those wherein py represents a 4 pyridinyl group even more preferred if py represents a dihalosubstituted 4 pyridinyl residue in the process object of the present invention the compounds of formula iii are generally used with respect to the compounds of formula ii in a molar ratio from 0 5 to 4 preferably they are used in a ratio from 0 8 to 1 5 even more preferably from 0 9 to 1 1 the present process is performed in the presence of an anhydride the term u201c anhydride u201d means a reagent selected in the group of the organic or inorganic anhydrides respectively derived from organic or inorganic acids or mixed including in this class also the acyl alkyl and arylsulfonyl halides examples of anhydrides utilizable in the present process are in the case.