Abstract: Liquid phase processable crystalline diacetylene polymers are obtained by the solid state reaction of monomers having the formulaR.sub.1 --C.tbd.C--C.tbd.C--R.sub.2where R.sub.1 and R.sub.2 are independently selected from the group consisting of(a) CH.sub.3 (CH.sub.2).sub.m --(b) HO(CH.sub.2).sub.n -- and(c) R.sub.3 NHOCO(CH.sub.2).sub.p --where "m" is an integer of from 0 to 15, "n" is an integer of from 1 to 15, "p" is an integer of from 1 to 15, and R.sub.3 is a member selected from the group consisting of(i) C.sub.6 H.sub.5 (CH.sub.2).sub.r --(ii) CH.sub.3 (CH.sub.2).sub.r -- and(iii) C.sub.10 H.sub.7 (CH.sub.2).sub.r --where "r" is an integer of from 0 to 11; with the proviso that where R.sub.1 and R.sub.2 are the same and are either (b) or (c), neither "n" nor "p" equals 1; and with the further proviso that where R.sub.1 and R.sub.2 are different and are either (b) or (c), the sum of "n" plus "p" is greater than 2.