Abstract: The present invention relates to novel hydrodipyranophthalazine compounds of the formula: ##STR1## wherein R.sub.1 = hydrogen or lower alkyl,R.sub.2 = hydrogen, chlorine or bromine,R.sub.3 = hydrogen or aralkyl if R.sub.2 = hydrogen,R.sub.3 = bromine or alkoxy if R.sub.2 = bromine,R.sub.3 = chlorine or alkoxy if R.sub.2 = chlorine, or ##STR2## wherein R.sub.4 = hydrogen, halogen, trifluoromethyl, alkyl, alkoxyl, alkylenedioxy, a possibly substituted amino group, or a nitro group,The 4,4'-bond is saturated or unsaturated, and acid-addition salts of these compounds.These compounds exert a valuable activity on the cardiovascular and central nervous system.