By 1992 he, Bin Ladin, Al Qaida, and Egyptian mujahideen were working out of the Sudan, thanks to the protection given them by Sudanese leader Hasan al-Turabi. Zawahiri twice visited the USA in search of funds in 1990, and was present at a major Islamic conference held in the Sudan (the Terrorist Internationale) in April 1991. When Bin Laden left Sudan in 1996 he left behind Al Qaida people who had supported Zawahiri's and its effort to assassinate Mubarak in Addis Ababa in 1995. The cells, with brother cells in Tanzania and Kenya, were then responsible for US embassy bombings in 1998.
In sum, the idea that Islamic Jihad and Al Qaida, and Zawahiri and Bin Ladin worked on parallel paths without intersection until 1998 is dead wrong. The two men have worked together since 1985, and their organizations were joined at the hip in 1988.