Coal pyrolysis at coking temperatures yields gases that are high in methane but very low in acetylene. Coal irradiated with laser light can produce gases rich in acetylene. The acetylene-to-methane ratio was shown to be related directly to the light flux at the surface of the decomposing coal. Temperatures cannot be measured directly, owing to the small crater size and the short duration of the laser pulse, but were estimated from equilibrium data. Temperatures can be changed by varying the energy of the laser beam, the laser focus, and the type of laser (ruby, neodymium, carbon dioxide). As the light flux increased from 190 w cm-2 to 375 kw cm-2, the c2h2/ch4 ratio increased from zero to 3.6 For Pittsburgh seam (HVAB) coal. Based on the gas composition and using published equilibrium data, temperatures were estimated as 1,160 deg to 1,250 deg k. Product gases were studied as a function of coal rank, particle size, and maceral.