Recently picosecond vibrationally resonant sum frequency generation (VRSFG) process has been adopted as a surface sensitive, chemically specific nonlinear imaging modality. In this talk, we will discuss our recent efforts to extend this technique to femtosecond regime. To this end, we have built a high powered mid infrared femtosecond optical parametric oscillator (OPO) tunable from 3-5 micron range. Use of femtosecond laser pulses exploits the broad bandwidth of mid infrared pulses to multiplex spectrum measurement and time resolve vibrational free induction decay to study dynamics.