We have developed a near-field scanning optical microscope (NSOM) with spectroscopic capability for application to advanced microelectronic materials and devices. Combining NSOM with spectroscopic analysis provides chemical information on thin films and defects with ultrahigh spatial resolution. Several microelectronic systems, InGaAs/InAlAs/GaAs epitaxial layers, partially fabricated SiO2/Si complementary metal-oxide semiconductor structures, and bulk samples of GaP and diamond, were examined in this work as vehicles to elucidate NSOM imaging modes. Reflected intensity contrast in NSOM provides images of defect networks in InGaAs/InAlAs/GaAs epitaxial layers and shows thickness variations in SiO2 films on Si. Fluorescence and Raman scattering modes are examined for chemically identifying materials and defects.