Synthesis of para‐Aryl‐Substituted Salicyldialdehydes

para-Substituted salicyldialdehydes are versatile molecular building blocks for porous organic cages, fluorescent dyes, spirobenzopyrans, homooxacalixarenes, dinuclear metal complexes, macrocycles, and cryptands. To date, no procedures for the synthesis of para-aryl-substituted salicyldialdehydes have been reported, which would broaden the scope of the above-mentioned topics, especially in the field of sensors and dyes, because the aromatic π systems can be enlarged and absorption or fluorescent events can be fine-tuned by various substituents. Herein, two synthetic routes to para-aryl-substituted salicyldialdehydes with both electron-withdrawing and -donating aromatic units are reported.