Multimodal nonlinear optical microscopy is a valuable tool to study complex biological samples. Here we present an easy-to-operate approach to perform coherent anti-Stokes Raman scattering (CARS), two-photon fluorescence (TPF), second harmonic generation (SHG), and third-harmonic generation (THG) imaging using a single laser source. Furthermore, inherently nonresonant-background-free CARS is demonstrated by controlling the polarization of three collinearly combined laser beams.