In conjunction to our ongoing study on aryl hydrazides, we have elaborated a new synthetic route to marine alkaloid ningalin C, D and G by way of dibenzo-carbazoles that are readily accessible from dinaphthyl hydrazides via [3,3]-sigmatropic rearrangement followed by cyclization of the resulting diamine products. Introduction of 3,4-dimethoxyphenyl groups and oxidations would complete the total syntheses of the above marine alkaloids. Presented herein will be our recent efforts toward the synthesis of poly-substituted naphthalenes and application to the synthesis of ningalin C, D and G