Since benzo [b] thiophene scaffold is one of the privileged structures in drug discovery as this core exhibits-activities for different biological problems, in this study bis (benzo[b]thiophene-2-yl) alkyl methanimine derivatives (1-9) were synthesized by reacting benzo[b]thiophene-2-carbaldehyde with diamines. All newly compounds were characterized by IR, H-1 NMR and C-13 NMR spectroscopic methods. Synthesized compounds were investigated using binary QSAR-based models on therapeutic activity prediction of synthesized compounds and they showed high predicted activities in following diseases: bacterial, angina, allergy, depression and obesity. Thus, they were then tested for their antimicrobial and antileishmanial activities as a result of this theoretical study. Compound 1(N, N'- (propane-1,3-diyl) bis (1-(benzo [b] thiophene-2-yl)) methanimine) was found the most active compound in both diseases. Thus, its molecular docking studies were also carried out.