We have observed simultaneous laser excitation of two or more radical species (OH, NH, CH, CN, and NCO) using a single, tunable wavelength in the reaction zone of various atmospheric pressure flames. Individual species are selectively detected by wavelength resolved fluorescence. An overlap among resonant transitions of OH, NH, CH, and CN occurs at 312.22 nm. Using this excitation wavelength, all four radicals may be measured simultaneously in both space and time. Both advantages and limitations are presented. Spectroscopic details on the excitation of CH(C2Σ+) near 314 nm, NCO(B2Πi) near 315 nm, and CN(B2Σ+) near 310 nm and 333 nm are reported. Following laser excitation of OH(A2Σ+), emission was observed from both NH(A3Πi) and CN(B2Σ+). This emission can be attributed to a surprisingly efficient collisional energy transfer from the excited OH(A) to NH(A) or CN(B). Collisional deactivation of CH(C2Σ+) to CH(A2Δ) and CH(B2Σ−) was observed and exploited to detect CH LIF in a spectral region free from NH, OH and CN interference. The diatomic radicals OH, NH, and CN all exhibit a small non-resonant laser excited fluorescence at low (0.05 J/cm2) power for any laser wavelength in this region.