  We present a group theoretic analysis of several classes of organic
superconductors. We argue that highly frustrated half-filled layered organic
superconductors, such as kappa-(ET)_2Cu2(CN)_3 (where ET is BEDT-TTF) and
beta'-[Pd(dmit)_2]_2X, undergo two superconducting phase transitions, the first
from the normal state to a d-wave superconductor and the second to a d+id
state. We show that the monoclinic distortion of kappa-(ET)_2Cu(NCS)_2 means
that the symmetry of its superconducting order parameter is different from that
of orthorhombic kappa-(ET)_2Cu[N(CN)_2]Br. We propose that quarter filled
layered organic superconductors, e.g., theta-(ET)_2I_3, have d_{xy}+s order
parameters.
