Initially, two variants of the coupe from the 140 series were offered: the 500 SEC (V8 engine, 235 kW/320 hp) and the 600 SEC (V12 en-gine, 290 kW/394 hp). In engineering terms, they were based on the S-Class sedans launched in 1991; unlike the predecessor coupes from the 126 series, however, they were stylistically more independent from the corresponding sedans.
Analogous to the other passenger car models from Mercedes-Benz, new model designations were introduced for the S-Class coupes as well in June 1993; the 600 SEC, for example, became the S 600 coupe.
Two fundamental technical innovations became available in the S 600 coupe for the first time: in May 1995, a completely newly developed five-speed automatic transmission with slip-controlled torque converter lock-up clutch and electronic control was introduced. Another innovation was the Electronic Stability Program ESP. In 1996, the model designations of the coupes were changed once again. The series was now called CL and this was no end in itself but reference to the fact that the large coupes had adopted the pacemaker function for the entire coupe family.