By reaction of heterocyclic-substituted 1-azo-naphth-2-ols with the Vilsmeier reagent or with strong acids polycyclic azolo[1,2,4]triazinium salts are formed in good yields. The azolo[1,2,4] triazinium salts exhibit similar UV=Vis absorption properties as the starting azo compounds, but in contrast to those the fluorescence appears in the visible range.