A set of 36 arylpiperazine derivatives with two novel complex terminal imide fragments, 8,11-dimethyl-3,5-dioxo-4-azatricyclo[5.2.2.0(2,6)]undec-8-en-1-yl acetate and 1,11-dimethyl-4-azatricyclo[5.2.2.0(2,6)]undecane-3,5,8-trione, were synthesized and tested for their affinity for 5-HT(1A) and 5-HT(2A) receptors. The Fujita-Ban analysis showed that the influence of structural modifications on the affinity for both receptor subtypes is additive and that the activity of similar compounds could be predicted with high accuracy. Compounds 46, 48 and 18 out of 14 screened in a functional model of anxiety and depression demonstrated antidepressant activity in the forced swimming tests in mice, and were devoid of neurotoxic effects (chimney test in mice).