Tetracyclic pyrido[2,3-b]azepine derivatives 4a-d and 4f as analogues of mirtazapine were synthesized via N-acyliminium ion cyclization by using aromatic rings such as benzene and thiophene ring as a ${pi}-nucleophile$, and evaluated for the binding affinity for ${alpha}2-adrenoceptor$. Among tested compounds, 2,3,9,13b-tetrahydro-1H-benzo[f]pyrrolo[2,1-a]pyrido[2,3-c]azepine (4a) was the most potent (Ki = 0.26 ${mu}M)$ but showed about 3-fold less binding affinity than mirtazapine (Ki = 0.08 ${mu}M)$ for a2-adrenoceptor.