Process for the selective production of ethylene, propylene and isoprene from light hydrocarbons comprising: a) fractionating a butane fraction in a de-isobutanizer to obtain an enriched iso-butane fraction and an enriched normal-butane fraction, b) cracking said normal-butane fraction and optionally an ethane fraction, optionally a propane fraction, in a non-catalytic cracking zone to produce an olefin rich stream, c) treating said olefin rich stream in a separating section to recover: an ethylene stream, a propylene stream, d) transforming the recovered iso-butane of step a) into iso-butene or t-butyl hydroperoxide or partly into iso-butene and partly into t-butyl hydroperoxide, e) optionally reacting iso-butene of step d), if any, with formaldehyde to make isoprene, f) optionally reacting t-butyl hydroperoxide of step d), if any, with an olefin to give an epoxide and t-butanol and further separating t-butanol, or optionally having t-butyl hydroperoxide of step d), if any, decomposed to t-butanol and reacted with formaldehyde to give isoprene, or reacting a part of the t-butyl hydroperoxide of step d) with an olefin and having the remaining part decomposed to t-butanol and reacted with formaldehyde to give isoprene, g) dehydrating the t-butanol recovered at step f), if any, into iso-butene and reacting said iso-butane with formaldehyde to make isoprene, or reacting directly the t-butanol recovered at step f), if any, with formaldehyde to make isoprene, or dehydrating the t-butanol recovered at step f), if any, into iso-butene, hydrogenating said iso-butene to iso-butane and oxidizing said iso-butane into t-butyl hydroperoxide, and recycling said t-butyl hydroperoxide, or dehydrating the t-butanol recovered at step f), if any, into iso-butene, then disproportionating said iso-butene and propylene recovered at step c) (or 2-butene recovered at step c)), separating an isoamylene stream and converting the isoamylene into isoprene by dehydrogenation, or making any combination of above routes of said step g), h) optionally disproportionating iso-butene of step d), if any, and propylene recovered at step c) (or 2-butene recovered at step c)), separating an isoamylene stream and converting the isoamylene into isoprene by dehydrogenation, at least one of steps e), f) and h) is not optional.