A dynamic pathway linking Pakistan flooding to East Asian heatwaves has been identified through observations and model experiments. In July to August 2022, Pakistan experienced severe flooding, while southern China faced intense heatwaves. These extreme events frequently coincide over the past 44 years, but the underlying mechanisms remain unclear. The study shows that convective heating over Pakistan induces upper-tropospheric divergent winds, which excite a barotropic anticyclone over eastern China, leading to persistent heatwaves. This dynamic pathway is intrinsic to the climate system and largely independent of global sea surface temperature forcing. The connection is most active during July to August when convective variability is large over Pakistan, and associated divergent flow excites barotropic Rossby waves that propagate eastward along the upper troposphere westerly waveguide. This robust waveguide and time delay offer hopes for improved subseasonal prediction of extreme events in East Asia. The study also highlights the role of atmospheric internal variability in linking Pakistan flooding and East Asian heatwaves, with results showing that the connection is largely independent of ENSO. The dynamic pathway involves convective heating over Pakistan inducing a baroclinic anticyclone, which leads to a barotropic Rossby wave train downstream, contributing to long-lasting heatwaves. The study confirms that the connection is intrinsic to the Asian summer monsoon system and is not primarily driven by global SST forcing. The findings suggest that the dynamic pathway is important for subseasonal prediction of extreme events in East Asia.A dynamic pathway linking Pakistan flooding to East Asian heatwaves has been identified through observations and model experiments. In July to August 2022, Pakistan experienced severe flooding, while southern China faced intense heatwaves. These extreme events frequently coincide over the past 44 years, but the underlying mechanisms remain unclear. The study shows that convective heating over Pakistan induces upper-tropospheric divergent winds, which excite a barotropic anticyclone over eastern China, leading to persistent heatwaves. This dynamic pathway is intrinsic to the climate system and largely independent of global sea surface temperature forcing. The connection is most active during July to August when convective variability is large over Pakistan, and associated divergent flow excites barotropic Rossby waves that propagate eastward along the upper troposphere westerly waveguide. This robust waveguide and time delay offer hopes for improved subseasonal prediction of extreme events in East Asia. The study also highlights the role of atmospheric internal variability in linking Pakistan flooding and East Asian heatwaves, with results showing that the connection is largely independent of ENSO. The dynamic pathway involves convective heating over Pakistan inducing a baroclinic anticyclone, which leads to a barotropic Rossby wave train downstream, contributing to long-lasting heatwaves. The study confirms that the connection is intrinsic to the Asian summer monsoon system and is not primarily driven by global SST forcing. The findings suggest that the dynamic pathway is important for subseasonal prediction of extreme events in East Asia.