However, one of the accused was acquitted by the court.
Arguments on quantum of punishment will take place on Thursday.
Eight serial bomb blasts had rocked Jaipur on May 13, 2008.
The four - Mohammad Saif, Mohammad Sarwar Azmi, Mohammad Salman and Saifurrehman were convicted under IPC sections 302 (punishment for murder), 307 (Attempt to murder), 324 (causing hurt by dangerous weapons, means), 326 (causing hurt by acid attack), 120-B (criminal conspiracy), 121-A (Conspiring to commit certain offences against State), 124-A (sedition), 153-A (promoting disharmony) and sections of Explosive Substances Act and Unlawful Activities (Prevention) Act, public prosecutor Srichand said.
He said the court has given benefit of doubt to the fifth accused Shahbaz Hussain and acquitted him.