Ultrafast electronic dephasing from the S-1(npi*) state and the energetics of the n = 3 Rydberg states of pyridine were studied by time-resolved photoelectron imaging in conjunction with (1+2') resonance-enhanced multiphoton ionization (REMPI) via the S-1 state. The lifetime at the S-1 origin was determined to be 32 +/- 5 ps from the decay of the total photoionization signal. Photoelectron energy and angular distributions observed for (1+2') REMPI clearly indicated that two-photon ionization from the S-1 state is being enhanced by the resonance with singlet 3s(n(-1)) and 3p(n(-1)) Rydberg states that have not been clearly observed before. The electronic energies of the 3p(x)(delta=0.57) and 3p(y)(delta=0.50) Rydberg states were determined for the first time, to be 56 120 and 57 140 cm(-1), respectively.