S-bearing species vs. COMs detection. Sources with detection of SO₂ are clustered by the amount of detected COMs in Yang et al. (2021). The numbers on the left of the source names indicate the amount of different COMs detected. The different colors indicate where the emission of CS or SO is seen. Those sources where the CS or SO emission is parallel to the outflow direction are usually rich in COMs, while sources where the CS or SO emission is perpendicular to the outflow direction do not show detection of COMs.