Substd 1,4-benzo dioxans useful as vasodilators, sedatives etc - prepd. from a benzaldehyde or acetophenone with a benzodioxan ketone or aldehyde

of formula (I) (where A = an alpha-keto ethylenic chain; R1 = H, OH, 1-3C alkoxy, benzyloxy or - or -OCH2COOH; R3 & R4 = 1-4C alkyl, or R3NR4 form a pyrrolidino, morpholino, piperidino, or hexamethylae imino ring; such that R = H when R2 = OCH2CH2NR3R4 or -OCH2COOHM and vice versa are useful for the treatment of circulatory and respiratory insufficiency, gastro duodenal ulcers, anxiety and nervousness, oedemas, inflammatory and other pain, asthma, visceral spasms, allergies and, depending upon (I), hypotension or hypertension.