Tautomeric forms of PPI dendrimers functionalized with 4-(4′-ethoxybenzoyloxy)salicylaldehyde chromophores

► SA chromophore groups are formed by bonding terminal groups to PPI dendrimers. ► SA chromophore groups reveal four most stable tautomeric forms. ► Tautomeric properties of SA groups depend on the dendrimer generation and solvent. ► Aggregation of SA chromophores facilitates formation of the trans-keto tautomers. ► Fluorescence of PPI SA dendrimers is attributed to nπ∗ states of keto tautomers.