Tajiks and Iranians have been connected historically and culturally for thousands of years. Tajiks, like the majority of Iranians, are an Iranian people and speak the Persian language, which is also the official language of Iran. Tajikistan, due to historical and cultural ties with Iran and the former Iranian empires, is regarded as a part of Greater Iran.
Post Arab revitalization of Persian culture began in Khorasan, the historic North-Easter Iranian province, under the Samanid dynasty. Samarqand and Bukhara flourished and became major trade, scientific and cultural hubs.
Tajik Independence 
Iran was the first nation to establish an embassy in Dushanbe. It was also one of the first countries to extend diplomatic recognition of the newly independent Tajikistan in 1991. Iran provided diplomatic assistance and built new mosques within Tajikistan. Due to the resurgence of Iranian culture within Tajikistan, Iran helped encourage cultural exchange through conferences, media, and film festivals. Iranian television programs, magazines, and books became increasingly common in Tajikistan.
However, despite the many things the nations have in common, there are also vast differences. Tajikistan's post communist government is secular while Iran's is Islamic. Furthermore, Iran is a predominantly Shia nation while Tajikistan is Sunni. The leading figures of the Islamic revival movement in Tajikistan have stated that Iran would not be a model for whatever Islamic government they advocate for Tajikistan.
Tajik Civil War 
During the civil war in Tajikistan, Iran offered to mediate between the two factions, however, these efforts did not produce any negotiations. In 1995, Tajikistan opened its first embassy in Tehran, one of the few outside of the former USSR. Relations have since grown stronger, as the two nations cooperate in the energy sector and officials from both nations have supported stronger ties.
Post Tajik Civil War 
President Ahmadinejad of Iran has commented that "Iran and Tajikistan are one spirit in two bodies". He also added that there are no limits to the expansion of relations between the two countries and that "We do not feel that we have a non-Iranian guest with us thanks to the many commonalities our two countries share".
On February 12, 2011, Tajik Foreign Minister Hamrokhon Zarifi, at an event in Dushanbe celebrating the anniversary of Iran's Islamic Revolution, stated: "Today, Tajik society is witnessing the Islamic Republic of Iran's activity and role in the growth and expansion of Tajikistan's economy." Zarifi referenced projects like the Sangtodeh-2 power plant, Anzob Tunnel and Istiklol Tunnel and as examples of Iran's role in the Tajik economy.
As of 2011 Iran is the second largest investor in Tajikistan after China.
Energy and Infrastructural Projects 
Sangtuda-2 Hydroelectric Power Plant
Revival of the Silk Road in the form of highways connecting China, Tajikistan, Afghanistan and Iran has been a major focus of the two governments.
Planned system will connect Tajikistan, Afghanistan and Iran.
Khatlon Cement Plant
Common TV channel
Common television channel to be broadcast in Iran, Afghanistan, Tajikistan.
- Tajikistan - Foreign Relations
- Ahmadinejad: Iran, Tajikistan one spirit in two bodies - CAUCAZ.COM
- "Tajik FM Stresses Iran's Key Role in Tajikistan's Economic Prosperity." Fars News Agency. Feb 12, 2011. Accessed Feb 12, 2011. http://english.farsnews.com/newstext.php?nn=8911231179