The　combined　nucleation　effect　of　graphene　oxide　(GO)　and　calcium　pimelate　(CaPi)　which　are　chemically　compound　together　(expressed　in　GO　−　CaPi)　in　isotactic　polypropylene　(iPP)　was　investigated.　Fourier　transform　infrared　(FTIR),　X-ray　diffraction　(XRD)　and　thermogravimetric　analysis　(TGA)　verified　that　CaPi　was　chemically　compound　with　GO　by　chelate　bonds.　The　crystallization　behavior　and　crystalline　morphologies　of　iPP　nucleated　with　different　mass　ratio　of　GO　and　CaPi　were　investigated.　The　crystallization　peak　temperature　of　iPP　nucleated　with　0.2　wt%　GO　−　CaPi　with　the　mass　ratio　of　1:5　(GO1　−　C5)　was　increased　by　8.3°C　when　compared　with　that　of　pure　iPP,　and　the　relative　content　of　β-crystal　reached　up　to　0.7962.　Whereas,　the　crystallization　peak　temperature　of　iPP　nucleated　with　0.2　wt%　GO　and　CaPi　which　are　blended　together　by　mechanical　force　(expressed　in　GO　+　CaPi)　with　the　mass　ratio　of　1:5　(GO1　+　C5)　was　only　increased　by　5.0°C.　It　was　attributed　to　that　the　aggregation　of　GO　+　CaPi　caused　the　decrease　of　the　crystallization　peak　temperature,　while　the　GO1　−　C5　uniformly　dispersed　in　the　iPP　matrix.　Unexpectedly,　the　relative　content　of　β-crystal　of　iPP　nucleated　with　0.02　wt%　GO1　−　C5　reached　up　to　0.8094,　and　the　crystallization　peak　temperature　was　increased　by　6.7°C　compared　with　that　of　pure　iPP.　Meanwhile,　the　impact　strength,　tensile　strength　and　heat　deflection　temperature　of　iPP　nucleated　with　0.02　wt%　GO1　−　C5　increased　by　almost　45.86%,　2.03%　and　7.7°C,　respectively.　The　iPP　nucleated　with　GO1　−　C5　obtained　a　balance　between　stiffness　and　toughness　and　the　thermo-mechanical　property　of　nucleated　iPP　was　improved.　©　2020　John　Wiley　&　Sons　Ltd