In this study, novel chlorine‐thymol derivatives (1,3‐bis(4‐chloro‐2‐isopropyl‐5 methylphenoxy)propan‐2‐ol (Thy‐OHI) and 2‐[2‐(4‐chloro‐2‐isopropyl‐5‐methylphenoxy)ethoxy]ethanol (Thy‐OHII)) and axially di‐4‐chloro‐2‐isopropyl‐5‐methylphenoxy (Thy‐SiPc), 1,3‐bis(4‐chloro‐2‐isopropyl‐5‐methylphenoxy)propanoxy (Thy‐OHI‐SiPc), and 2‐[2‐(4‐chloro‐2‐isopropyl‐5‐methylphenoxy)ethoxy]ethanoxy (Thy‐OHII‐SiPc) substituted silicon phthalocyanine compounds were obtained, and their structures were elucidated by the combination of various methods such as NMR, IR, UV–Vis, and MS. The inhibitory effects of these compounds (Thy‐OHI, Thy‐OHII, Thy‐SiPc, Thy‐OHI‐SiPc and Thy‐OHII‐SiPc), synthesized for the first time, on cholinesterase enzymes (AChE and BChE) were investigated in the laboratory environment. In the studies, notably Thy‐OHI‐Si and thymol derivative ligand Thy‐OHII displayed significant inhibition against AChE and BChE.