Palladium-mediated coupling of 2-(4-iodoaryl)-1,2,4-triazine-(2H,4H)-3,5-diones with variously substituted vinylstannanes has been examined in efforts to explore the SAR of novel triazine anticoccidials. Conventional procedures were employed for the large-scale preparation of key iodoaryltriazine intermediates while a new method - employing a modified Shapiro reaction - was developed for the synthesis of 1,1-substituted vinylstannanes.