Abstract: The invention relates to new thiazolo[4,5-c]quinoline derivatives of the general Formula I ##STR1## and acid addition salts thereof, a process for the preparation of the same and pharmaceutical compositions comprising the said compounds.The substituent definition of the general Formula I is as follows:R stands for hydrogen; a straight or branched chained alkyl group having 2-5 carbon atoms optionally substituted by one or more halogen atom(s); phenyl or phenyl-(lower alkyl) optionally bearing one or more substituent(s) on the phenyl ring;R.sup.1 and R.sup.2 are identical or different and stand for hydrogen, halogen or lower alkyl).The compounds of the general Formula I possess valuable central nervous depressive properties.