The high-temperature pyrolytic reaction of (CH3)3Al with H2S followed by trapping into argon matrices at 14 K has led to the formation and isolation of molecular Al2S3. Identification was made based on band positions, lack of deuterium shift, the observation of CH3D when D2S was employed, and a poor spectral match to known aluminum sulfides and by analogy to the molecular species B2O3 and Al2O3. The spectra are suggestive of a V-shaped molecule, also similar to B2O3 and in contrast to the linear structure of Al2O3. Local density functional calculations were also carried out in support of the experimental work. Reaction of (CH3)3Al with methyl and ethyl mercaptan led to the formation of (CH3) 2AlSR (R = CH3, C2H5), probably in the known dimeric structure.