Effect of aromatization of the ring on intramolecular H-bond in 3-hydroxy-4-formylo derivatives of fulvene

► In aromatized fulvene derivative the intramolecular hydrogen bond is strengthened. ► Shannon Aromaticity and pEDA are in agreement with well-known HOMA and NICS indices. ► HOMA shows the RAHB character of the intramolecular hydrogen bond.