Copper　complexes　that　can　experience　reversible　heat-induced　dehydration　and　rehydration　in　the　solid　state　were　rarely　reported　although　thermochromic　copper　complexes　have　been　widely　reported,　and　their　heat-induced　magnetic　properties　have　not　been　studied.　We　firstly　observed　the　reversible　thermochromic　phenomena　of　the　known　copper(II)　complex　[Cu(bpy)(OOCCH　3　)　2　]　n　•xnH　2　O　(x　=　2.5　or　3;　bpy　=　4,4＇-bipyridine)　in　the　solid　state,　which　is　associated　with　the　dehydration　and　rehydration　processes,　and　found　that　heat-induced　coloration　clearly　enhanced　the　magnetic　susceptibility.