A process is provided, comprising reacting a (hetero)aryl 1,3-dipole compound with a (hetero)cycloalkyne, wherein the (hetero)aryl 1,3-dipole compound comprises a 1,3-dipole functional group bonded to a (hetero)aryl group, and wherein the (hetero)aryl 1,3-dipole compound is a (hetero)aryl azide or a (hetero)aryl diazo compound； wherein:(i) the (hetero)aryl group of the (hetero)aryl 1,3-dipole compound comprises a substituent(ii) the (hetero)aryl group of the (hetero)aryl 1,3-dipole compound is an electron-poor (hetero)aryl groupand wherein the (hetero)cycloalkyne is a (hetero)cyclooctyne or a (hetero)cyclononyne according to Formula (1). The invention also relates to the products obtainable by the process according to the invention.
