A multicomponent reaction of -naphthol, dimethyl malonate, and aromatic aldehydes in the presence of NbCl5 as promoter is described. Under similar conditions, aromatic aldehydes with different substituents exhibited different behaviors than -naphthol and dimethyl malonate. In these MCRs, 4-aryl-3,4-dihydrobenzo[f]coumarins are obtained as the major products (41-93%) and 14-aryl-14H-dibenzo[a,j]xanthenes as the minor products (1-38%).Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)