Symphony has no guitar and saxophone.

Not all of them. A standard orchestra doesn't have two instruments. Guitar is so quiet that you can hardly hear it in a big band. Saxophone, the sound has been covered by clarinet, so it is generally not needed unless there is special demand.

But there are also composers who use this instrument. Rossini accompanied a scene with a guitar in his opera. When Ravel made the band version for the photo exhibition, he simulated the sound of the Armenian musical instrument Ducko on the saxophone. Shostakovich wrote a set of works now called "Second Jazz Suite", but its original name was "Suite for Orchestra with Unconventional Instruments". There are a large number of "unconventional instruments" like accordion and saxophone.