An efficient and environmentally friendly multicomponent synthesis of substituted 1,8-naphthyridines catalyzed by bismuth(III) nitrate pentahydrate [Bi(NO3)3 x 5H2O] under solvent-free microwave irradiation is described. This procedure has such advantages as short reaction time, high yields, and simple workup. The catalyst could be reused several times, keeping its initial activity recycled reactions.