"mutually fruitful" is correct and usable in written English.
You can use it to describe a relationship or situation between two or more parties that is beneficial to all involved. For example, you could say, "The agreement between the two companies was mutually fruitful, resulting in increased profits for both."
The pair's collaboration had been mutually fruitful.
Although Stravinsky wrote only four scores for ballets by George Balanchine, the two artists had a long and mutually fruitful working relationship.
Dr. Messner was one of the first international faculty recruited by Dr. Chidziva to help nurture the new residency and establish a mutually fruitful relationship that continues to grow.
In other words, carving out a sustainable future for VGM will also involve taking the corresponding industry convergence seriously laying down the proper financial and technical foundations for more structured, mutually fruitful collaborations between the music and gaming businesses.
However, forging mutually fruitful relationships between science and policy has proven to be a difficult task (Boehmer-Christiansen 1994).
Conversely, synergy is a positive-sum self-reinforcing game because it favors the recurrence and multiplication of mutually fruitful interactions, hence a possible divergence from a status quo.
"Sberbank's cooperation with Microsoft is long-term, fruitful and mutually beneficial," the bank chairman, Andrei Kazmin, said afterward, according to the Interfax news agency.
Over the past decades, behaviour and cognitive psychology have produced fruitful and mutually converging theories from which hypotheses could be derived on the nature and origin of fear and anxiety disorders.
Unfortunately, this is less widely so between Anglo-American and Latin American groups, despite the existence of considerable room for fruitful and mutually beneficial interaction.
They proposed that, when specific research funding was difficult to obtain, collaboration between qualified professionals and pre-registration students could provide a fruitful and mutually advantageous environment where professionals could engage with the research process on specific projects.
Further experimental pursuit of both hypotheses would be fruitful, noting that the two scenarios are not mutually exclusive and that both may contribute to the evolvability and robustness of information in ciliate genomes.
