Ammonia　is　an　important　chemical　and　a　carrier　of　hydrogen.　Artificial　nitrogen　fixation　mainly　relies　on　the　Haber−Bosch　process　(HB)　driven　by　thermo-catalysis,　where　the　activation　of　N2　usually　follows　a　dissociative　route.　Nonetheless,　an　associative　route　is　common　in　electrocatalytic　or　biological　nitrogen　fixation　under　ambient　conditions.　Recently,　it　was　reported　that　N2　can　be　activated　via　an　associative　mechanism　in　thermocatalytic　ammonia　synthesis　over　some　special　catalytic　materials　or　active　sites,　which　exhibits　enormous　potential　to　realize　efficient　ammonia　synthesis　under　relatively　mild　conditions　(≤　400　°C　and　≤　1　MPa).　In　this　review,　we　focus　on　the　recent　progress　of　ammonia　synthesis　that　follows　an　associative　mechanism.　Besides　the　hydride　and　nitride　materials,　the　catalysts　with　highly　dispersed　active　sites　are　included.　We　discuss　the　key　factors　that　drive　N2　activation　via　an　associative　route　and　examine　their　correlation　with　catalytic　performance.　Finally,　we　delve　into　the　perspectives　of　catalyst　design　tailored　to　facilitate　an　associative　mechanism.　©　2024