The synthesis, affinities for 5-HT 1 A , 5-HT 2 , D 1 , D 2 , α 1 and α 2 receptors and structure-activity relationships are described for a series of arylpiperazines substituted on the N-4 atom with an ω-(2-naphthothiazole)alkyl chain. The best affinity for 5-HT 1 A receptors was obtained for 1-(2-methoxyphenyl)piperazine derivatives with IC 5 0 values in the range 3.2-12 nM; however, for all the reported compounds mixed 5-HT 1 A /D 2 /α affinities were observed.