The　hydrothermal　reactions　of　Co(OAc)(2)center　dot　4H(2)O,　3,5-dinitrosalicylate　(3,5-(NO2)(2)sal)　and　2,2＇-bipyridine　(2,2＇-bipy)　with　different　reaction　periods　give　metallamacrocycles　1　and　2　with　the　same　chemical　formula　CO4(2,2＇-bipy)(4){3,5-(NO2)(2)sal}(4).　Replacing　Co(OAc)(2)center　dot　4H(2)O　with　Zn(NO3)(2)center　dot　6H(2)O,　using　the　same　synthetic　procedures,　results　in　the　formation　of　compound　[Zn(2,2＇-bipy)-{3,5-(NO2)(2)sal}],　(3)　with　a　1D　chain　structure　and　the　metallamacrocycle　compound　Zn-4(2,2＇-bipy)(4){3,5-(NO2)(2)sal}(4)　(4).　Compounds　1　and　2　crystallize　as　two　different　polymorphs　of　cyclic　tetranuclear　compounds.　Compounds　3　and　4　are　polymorphic　too.　The　compounds　1　and　4　are　isomorphous.　The　weak　coordination　interactions　have　significant　influence　on　the　spacial　orientations　of　the　3,5-(NO2)2sal　ligand,　and　may　affect　the　crystallization　processes.　There　are　antiferromagnetic　interactions　in　the　cyclic　tetranuclear　cobalt(II)　compounds　1　and　2.　Compound　3　exhibits　weak　fluorescent　emission　in　the　solid　state　at　room　temperature.　(c)　2007　Elsevier　Ltd.　All　rights　reserved.