The copper(I) complex [Cu(C18(6)tren)] Br 1 (C18(6)tren = tris(2-dioctadecylaminoethyl) amine) which exhibits a good stability towards aerobic conditions is a versatile, highly reactive and recyclable catalyst for the Huisgen cycloaddition of azides with terminal or internal alkynes and is a useful catalyst for the preparation of "click'' dendrimers.