Green conversion of three‐dimensional organometallic [Ag2(μ6‐tp)]n (1) coordination polymer (CP) nanosheets, prepared by sonochemical procedure, to three‐dimensional organometallic [Ag2(μ4‐tp)(apy)2]n (2) (where H2tp = terephthalic acid and apy = 2‐aminopyridine) CP nanoparticles has been observed upon solid‐state mechanochemical reaction of compound 1 with 2‐aminopyridine. The AgO3Ag···C6 coordination sphere of silver ion in 1 changed to NO2Ag···C coordination sphere in 2 during this mechanochemical addition. These samples were characterized by infrared spectroscopy, thermogravimetric and differential thermal analyses, X‐ray powder diffraction and scanning electron microscopy.