Time-resolved resonance Raman spectra for triplet 4-methoxyphenyl nitrene and 4-ethoxyphenyl nitrene and their dimerization reaction to form azo dimer products in acetonitrile solution on the nanosecond time scale are reported. As the 4-methoxyphenyl nitrene and 4-ethoxyphenyl nitrene Raman bands decay, the Raman bands for the azo dimer products increase in intensity. The triplet 4-methoxyphenyl nitrene and 4-ethoxyphenyl nitrene species and their reaction to produce azo products are compared to a recent study of the 2-fluorenyl nitrene species and its reaction to form dehydroazepine ring-expansion products. The properties of the singlet and triplet arylnitrenes and their reaction mechanisms to form azo dimer and ring-expansion products are briefly discussed.