Tailoring　the　magnetic　properties　of　semiconductors　is　crucial　for　realizing　spintronic　devices　with　integrated　logic　and　memory　functions.　Graphdiyne　(GDY),　a　two-dimensional　carbon　semiconductor,　has　emerged　as　a　promising　material　for　this　purpose.　This　work　demonstrates　an　effective　approach　to　induce　robust　room-temperature　ferromagnetism　in　GDY　through　in-situ　transition　metal　(Fe,　Co,　Ni)　doping　via　an　improved　liquid-liquid　interface　synthesis　method.　Density　functional　theory　calculations　reveal　that　the　ferromagnetism　originates　from　the　Kagome　lattice　formed　by　the　doped　transition　metal　atoms.　Remarkably,　Fe-doped　GDY　exhibits　a　saturation　magnetization　of　2.86　emu　·　g−1　at　room　temperature,　substantially　higher　than　Co-　and　Ni-doped　counterparts.　Furthermore,　post　synthesis　annealing　treatment　allows　modulating　the　magnetic　properties　by　introducing　hydroxyl　groups,　with　Co-GDY　annealed　at　500°C　showing　optimal　room-temperature　ferromagnetic　behavior　(0.26　emu　·　g−1).　This　work　paves　the　way　for　tailoring　magnetic　semiconductors　for　spintronic　applications　by　leveraging　transition　metal　doping　and　defect　engineering　in　graphdiyne.　©　2024　Elsevier　B.V.