Bicyclothiazoles having the structure: ##STR1## wherein n is 3, 4, or 5R.sub.1 is hydrogen or alkyl,R.sub.2 is hydrogen, alkyl, hydroxyl, alkoxy, cyano, phenyl, carboxyl, tetrazole, or halogen,R.sub.3 is tetrazole, carboxamide or ##STR2## wherein Z is oxygen, sulfur, or NH andR.sub.4 is H, alkali metal, ammonium, alkyl, alkoxyalkyl, aryl, or aralkyl,are novel and useful as antiallergic agents. The compounds are formulated with a pharmaceutical carrier for oral, parental, inhalational, or rectal means of administration.