Reactions of 10-(4-aminopiperazino)-10,11-dihydrodibenzo[b,f]thiepins XIVa-XIVd with benzaldehyde, 3,4-dimethoxybenzaldehyde, 4-dimethylaminobenzaldehyde, salicylaldehyde, 3-ethoxy-4-hydroxybenzaldehyde, 2-(2-dimethylaminoethoxy)benzaldehyde, 3-(2-dimethylaminoethoxy)benzaldehyde and 3-ethoxy-4-(2-dimethylaminoethoxy)benzaldehyde afforded a series of 19 hydrazones IIIa-Xc. Some of them showed the expected anticonvulsant effect but only towards pentetrazole; antagonism of maximal electroshock seizures was not observed. In general, the products have a character of tranquillizers: in higher does they produce central depression, potentiate the thiopental sleeping time, have hypothermic action; in single cases antiamphetamine, antireserpine, antihistamine and cataleptic effects were observed. The water-soluble salts of the basic hydrazones VIIIa, VIIIc, IXc and Xc, administered parenterally, showed a rather high acute toxicity and revealed also adrenolytic and hypotensive activity.