In the transitional period of 7^th to 9^th century the intellectual and cultural city of Hillah contributed to Iranian culture in three forms; scientific (through scholars and intellectuals’ journeys), spiritual (Hajj pilgrimage) and economic (commercial caravans), all of which were embodied in three dimensions of religion, mysticism and intellectual quests in Iranian culture. In terms of religion and science, Allameh Helli and his son Fakhr-al-Mohaqqeqin played a prominent role in transferring Hillah knowledge to Iran to the extent that their role was crucial in Iranians’ conversion from Sunni to Shia Islam. From a mystic and spiritual point of view, in addition to contributions from Seyyed ibn Tavous and Ibn Meysam Bohrani, Ibn Fahad Hilli and Seyyed Heydar Amoli, their role in bilateral relations were highly effective.