This work describes the synthesis and quadratic nonlinear optical properties of hybrid nanoparticles. These nanoparticles are based on the insertion of the push―pull 4-[2-(4-dimethylaminophenyl)azo]-1-methylpyridinium chromophore in the manganese hexathiohypodiphosphate MnPS 3 inorganic matrix. The included chromophores form J-aggregates responsible for second harmonic generation (SHG). The nanoparticles are characterized by infrared and UV―visible spectroscopy and by transmission electronic microscopy. The SHG efficiency of the particles dispersed in a polymer thin film is studied by polarized nonlinear microscopy, which permits probing of both the efficiency of the nanoparticles and their intrinsic molecular order. They are seen to assemble in 100-300 nm size agglomerates whose morphology, depending on the preparation, can lead to a collective optimal one-dimensional arrangement of the nanoparticles resulting from interparticles interactions.