Two new divalent metal constructions were synthesized upon chelation reactions between 2-(ptolylamino)acetohydrazide ligand (HL) and Co(II), Ni(II) chloride salts. The structure of achieved compounds was identified by conducting a series of spectral and physicochemical techniques. A mixture of distilled water and DMSO was used for preparing four different concentrations of the tested compounds; (50, 100, 200 and 300 ppm), which were then used in treating Eobania vermiculata under laboratory conditions. The thin-layer film technique was utilized for performing the in vitro treatments. The sub-lethal concentrations; (LC25 and LC50) values were estimated. The investigated chemical compounds displayed remarkable toxicological effects against the screened brown garden snails. Eobania vermiculata species showed the highest sensitivity level toward Ni(II) complex (LC50 = 53.55 ppm). However, the (HL) ligand displayed a higher toxicity against Eobania vermiculata than Co(II) complex (LC50 = 87.92 and 95.59 ppm, respectively). The investigated land snails were treated in vitro with the LC25 concentration of the obtained compounds for 7 days to evaluate their efficacy on the shell of those species. The level of some elements composing the snail shell; calcium, magnesium, phosphorus and potassium, was assessed. The obtained data emphasized that the tested compounds caused a considerable decrease in the level of estimated shell elements.