p-Nitrophenylchlorocarbene (PNPCC) was studied by laser flash photolysis with UV-vis detection in solution at ambient temperature. The pi -> p (316 nm) and sigma -> p (628 nm) absorptions of PNPCC were replaced in pi- or O-donor solvents by absorptions due to pi- or O-ylidic complexes or O-ylides. Donors included anisole, 1,3-dimethoxybenzene, 1,3,4,5-tetramethoxybenzene, diethyl ether, 18-crown-6, and dibenzo-18-crown-6. Suggestive evidence was also obtained for weak pi-complexation of PNPCC by benzene. Computational studies aided in understanding the carbene complex and O-ylide absorption spectra, and they provided structures and energetics for these species.