Married biotech moguls Sachiko Kuno and Ryuji Ueno, who own two of the most prominent historical properties in Georgetown and run a foundation in their names, are splitting —  this according to divorce papers filed last month in Montgomery County.

The breakup could prove complicated, given the couple’s vast real estate portfolio, network of philanthropic works, and interests in the drug company they co-founded.

Kuno, 61, and Ueno, 62, first made headlines in 2011 when they turned out to be the whispered-about mystery buyers of the famed Evermay estate, the vintage 1801 manse they picked up for $22 million. Interest in them reached a fever pitch shortly thereafter, when they scooped up another eight-figure Georgetown property, Halcyon House, for $11 million. (Rumors abounded, including a particularly persistent one that Kuno wanted a tony Georgetown property just for her cat.)

From there on out, their names popped up as potential buyers any time a prime Washington property hit the market.

The couple, originally from Japan, never lived in either home, but maintained a residence in Potomac, Md. — or rather, a complex of five neighboring homes, connected by paths, according to a 2012 Washington Post profile. Their plan had been to live at Evermay and use Halcyon House as the base of a philanthropic incubator project that houses and coaches would-be entrepreneurs. Though their buying spree made them the talk of Georgetown, little is known about the intensely private pair, who were married in 2002 after each went through a divorce (Ueno has two grown sons from his first marriage).

In the Montgomery County court filings, Kuno said the divorce was uncontested and that she and Ueno have lived apart since September 2014.

One thing we know: their deep pockets come courtesy of Sucampo Pharmeceuticals, the Bethesda-based company they cofounded and took public in 2007. It produces Amitiza, a drug used to treat constipation, including the opioid-induced variety.  Together, they also created the S & R Foundation (the name comes from their combined first initials), which funds the Halcyon Incubator, the Evermay Chamber musicians, and gives out awards to artists, scientists, and other innovators. The foundation purchased the Fillmore School building in Georgetown last year for $16.5 million, and just announced it would offer artists free studio space in the historic property.

A call to Sucampo was referred to the foundation, which released a statement saying the organization’s work would continue despite the divorce. “Both Drs. Kuno and Ueno remain steadfast in their commitment to the Washington, DC region and international cultural collaboration. Accordingly, S&R will continue to grow its support of talented individuals in the arts, sciences, and social enterprise with a continued focus on its unique fellowship programs and incubation methodology, providing time, space and support to allow innovators to think and act boldly and with purpose.”