Carboxylate zinc complexes of general formula [Zn2L x(p-OOC-C6H4-CHO)], [Zn2L x(o-OOC-C6H4-COOH)], [(Zn2L x)2(OOC-CH2-COO)], [(Zn2L x)2(OOC-CH2CH2-COO)] and [(Zn 2Lx)2(p-OOC-C6H4-COO)] (x = 1, 2; H3L1 = 2-(2-hydroxyphenyl)-1,3-bis[4-(2- hydroxyphenyl)-3-azabut-3-enyl]-1,3-imidazolidine and H3L2 = 2-(5-bromo-2-hydroxyphenyl)-1,3-bis[4-(5-bromo-2-hydroxyphenyl)-3-azabut-3- enyl]-1,3-imidazolidine) were isolated with different solvates. The crystal structures of [Zn2L1(p-OOC-C6H 4-CHO)]·2.5DMSO·2H2O, [(Zn2L 1)2(OOC-CH2CH2-COO)]·4. 25H2O·0.75MeOH·0.5MeCN, [(Zn2L 2)2(OOC-CH2CH2-COO)]·7H 2O·0.25MeOH and [(Zn2L1) 2(p-OOC-C6H4-COO)]·2.5H 2O·MeOH·6EtOH demonstrate that their different nuclearities are a function of the carboxylate donor, with the aldehyde residue remaining uncoordinated in [Zn2L1(p-OOC-C 6H4-CHO)]·2.5DMSO·2H2O. The solution studies further support the dissimilar nuclearity of the complexes and agree with a dinuclear nature for those complexes containing ortho-phthalate or 4-formylbenzenecarboxylate, and a tetranuclear arrangement when malonate, succinate or terephthalate are used as co-ligands. The ability of both Schiff base ligands to recognize Zn(ii) in solution was studied by UV-vis and emission spectroscopies. The luminescent properties of the ligands and their isolated complexes are also discussed in detail.