Optical–optical double-resonance spectroscopy has been used to record a high-resolution spectrum of the C˜2Π(000)–A˜2Π(000) transition of SrOH. Rotational and fine structure parameters have been determined for the C˜2Π state through a combined least-squares fit with the A˜2Π–X˜2Σ+ optical transition data and the millimeter-wave pure rotational data of the X˜2Σ+ state. The spin-orbit constant of the C˜2Π state was found to be 24.6607cm −1 , which is significantly smaller than in the à 2 Π state. This change can be rationalized by the different atomic orbital character of the à 2 Π and C˜2Π states. The values of the Λ-doubling constants in the C˜2Π state have been examined in terms of the pure procession model. The agreement between the calculated and observed Λ-doubling constants suggests that the C˜2Π state may form a unique perturber pair with the nearby D˜2Σ+ state.