An optical film comprising: a substrate having front and rear surfaces, and at least one solid optical retardation layer on the front surface of the substrate, wherein the solid optical retardation layer comprises rigid rod-like macromolecules comprising n organic units of the first type having general structural formula I and k organic units of the second type having general structural formula II wherein n is in the range from 5 to 10,000, and k is in the range from 5 to 10,000, R 1 and R 2 are side-groups independently selected from the list comprising -H, alkyl, -(CH 2) m SO 3 M, -(CH 2) m Si(O-alkyl) 3, -CH 2 -aryl, -(CH 2) m OH, wherein m is a number from 1 to 18, and in case -H is one of the side-groups, then its fraction does not exceed 50% of total number of side-groups in the macromolecule, and M is a counterion selected from the list comprising H +, Na +, K +, Li +, Cs +, Ba 2+, Ca 2+, Mg 2+, Sr 2+, Pb 2+, Zn 2+, La 3+, Al 3+,Ce 3+, Y 3+, Yb 3+, Gd 3+, Zr 4+ and NH 4-p Q p +, wherein Q is selected from the list comprising linear and branched (C1-C20) alkyl, (C2-C20) alkenyl, (C2-C20) alkynyl, and (C6-C20)arylalkyl, and p is 0, 1, 2, 3 or 4; wherein the organic units of the first type and the organic units of the second type are contained in the rigid rod-like macromolecules in random or orderly sequence, wherein the rigid rod-like macromolecules are isotropically oriented in the plane of the substrate, the solid optical retardation layer is a negative C-type, and the solid optical retardation layer is substantially transparent to electromagnetic radiation in the visible spectral range. a substrate having front and rear surfaces, and at least one solid optical retardation layer on the front surface of the substrate, wherein the solid optical retardation layer comprises rigid rod-like macromolecules comprising n organic units of the first type having general structural formula I and k organic units of the second type having general structural formula II wherein n is in the range from 5 to 10,000, and k is in the range from 5 to 10,000, R 1 and R 2 are side-groups independently selected from the list comprising -H, alkyl, -(CH 2) m SO 3 M, -(CH 2) m Si(O-alkyl) 3, -CH 2 -aryl, -(CH 2) m OH, wherein m is a number from 1 to 18, and in case -H is one of the side-groups, then its fraction does not exceed 50% of total number of side-groups in the macromolecule, and M is a counterion selected from the list comprising H +, Na +, K +, Li +, Cs +, Ba 2+, Ca 2+, Mg 2+, Sr 2+, Pb 2+, Zn 2+, La 3+, Al 3+,Ce 3+, Y 3+, Yb 3+, Gd 3+, Zr 4+ and NH 4-p Q p +, wherein Q is selected from the list comprising linear and branched (C1-C20) alkyl, (C2-C20) alkenyl, (C2-C20) alkynyl, and (C6-C20)arylalkyl, and p is 0, 1, 2, 3 or 4; wherein the organic units of the first type and the organic units of the second type are contained in the rigid rod-like macromolecules in random or orderly sequence, wherein the rigid rod-like macromolecules are isotropically oriented in the plane of the substrate, the solid optical retardation layer is a negative C-type, and the solid optical retardation layer is substantially transparent to electromagnetic radiation in the visible spectral range.