Brønsted acid-promoted cascade synthesis of novel (E)-6-phenyl-7-styryl-5,6-dihydrodibenzo[b,h][1,6]naphthyridines has been achieved via homodimerization of 2′-aminochalcones by employing sodium dodecylsulphate (SDS) as a surfactant in water. Besides water as an environmentally benign reaction medium, the reaction proceeds smoothly with high atom-economy under a sequential one-pot protocol.