"We actively cooperate in international organizations. We support each other constantly on every issue," Aliyev said at a joint news conference in Baku. "We have very solid political relations."
Rahmon told reporters that relations between the two nations are becoming closer.
"[Our] countries have decided to fully use the existing opportunities to increase the commodity turnover, to accomplish joint economic projects, and to establish close cooperation in all directions," Rahmon said.
Rahmon also addressed concerns over Iran's nuclear program, which it has vowed to pursue in the face of intense international pressure.
"Concerning the tension around Iran," Rahmon said, "I would like to say that we cannot be indifferent to the fate of this country, which we are connected to by cultural, linguistic, and other community ties. We are convinced that all the burning issues can be solved only by use of diplomatic means."
Azerbaijan's state media quote Aliyev as saying his country will open an embassy in Dushanbe by the end of this year.
It is the Tajik president's first official visit to Azerbaijan.
Aliyev traveled to Tajikistan in March.
RFE/RL Central Asia Report
SUBSCRIBE For regular news and analysis on all five Central Asian countries by e-mail, subscribe to "RFE/RL Central Asia Report."