TEHRAN — The old brewery was a cockroach-infested ruin, a makeshift shelter for drug addicts in Tehran’s bustling downtown. Most people walked straight past it, a festering eyesore in a city dominated by high rises and building cranes.

But when Hamidreza Pejman, a sweatpants-wearing art lover with a mission to bring Iranian art to a global level, stumbled across the building he saw something else: a space to exhibit international art and build bridges between Iranian and foreign artists. “A place where art can be art,” he said, “no matter the costs.”

Mr. Pejman, 36, who once scrubbed toilets in London but got rich in construction in Iran, took out his checkbook and bought the brewery last year.

In the two years that his nonprofit Pejman Foundation has been active, he has not only bought loads of Iranian art, but also supported dozens of Iranian and foreign artists.