The phrase "allowing not only" is correct and usable in written English.
It is typically used to introduce a clause that indicates multiple possibilities or benefits resulting from a particular action or situation.
Example: "The new policy is beneficial, allowing not only for increased productivity but also for improved employee satisfaction."
Alternatives: "enabling not just" or "permitting not only".
The Opus connects to the Internet, allowing not only for online radio, but giving users remote control once its included software is installed on a touch-screen P.D.A.
Instead of tidy single-party control, or a two-party coalition, politics has become increasingly fragmented, allowing not only the Greens but also new right-leaning parties to force new alignments.
In 1991 a rare right-wing government passed a law allowing not only charities, religious organisations and groups of parents but also businesses to open schools and get as much state money per student as state-run ones.
On a personal level, Obama had to feel that he had somehow failed one of his mentors, allowing not only Kennedy's seat to slip away but quite possibly his dream of national health care too.
Accordingly, Mr. Luxemburg said, the model lease contains specific provisions allowing not only for late charges and assessments, but also for the imposition of "user charges" -- on either a per-share basis or on the basis of actual usage -- for services like water and electric utilities, and facilities like parking garages, health clubs and storage areas.
The approach is based on an object-oriented structuring allowing not only central control units but also distributed control units as needed by today's designs.
And a narrative structure was adopted that allows not only for extended but for infinite treatment.
He has been allowed not only to live in what one US official called a "studio" in Camp Echo.
Better still, as this book shows, they allow not only birds but the human imagination to take flight.
Employees were allowed not only to choose how to fulfil their orders, but also to trade on their own account.
Israel's "law of return" allows not only Jews but their partners, children and grandchildren, who may not be technically Jewish, to claim Israeli citizenship.
