A typical job sequencing problem is studied in this research to improve productivities in manufacturing companies. The problem consists of two-stage parts and assembly processes. Two parts are provided independently each other and then two sequential assembly processes are followed. A new heuristic is developed to solve the new type of sequencing problem. Initial solution is developed in the first stage and then the initial solution is improved in the second stage. In the first stage, a longer part manufacturing time for each job is selected between two, and then a sequence is determined by descending order of the times. This initial sequence is compared with Johnson's sequence obtained from 2-machine assembly times. Any mismatches are tried to switch as one possible alternative and completion time is calculated to determine whether to accept the new sequence or not to replace the current sequence. Searching process stops if no more improvement can be made.