Problem in plotting complex valued data in Mathematica

Question

I have a situation where a function sys yields solutions in complex values while I change its argument `x from $-\pi$ to $+\pi$ as in the following:

Bands[sys[t1, t2, 3], {x, -\[Pi], \[Pi]}]

which gives me list of complex values with x as following:

{{-3.14159, -1.99705 + 0.0000290634 I}, {-3.02073, -1.99703 - 
0.0000293392 I}, {-2.8897, -1.99698 - 
0.0000302499 I}, {-2.76735, -1.99691 - 0.0000316411 I},...{3.14159, 1.99705 
+0.0000290634 I}}

Now if I write

Re[Bands[sys[t1, t2, 3], {x, -\[Pi], \[Pi]}]]

it gives me correct list of real parts of the complex values which is:

{{-3.14159, -1.99705},{-3.02073, -1.99703},{-2.8897, -1.99698}...so on} but for imaginary parts:

Im[Bands[sys[t1, t2, 3], {x, -\[Pi], \[Pi]}]]

it gives me:

{{0,0.0000290634 I},{0,- 0.0000293392 I},{0,- 0.0000302499 I}...so on}

thus, not showing the correct values of variable x. As a result, the real values giving me correct plot but the imaginary values don't give me correct plot since the values of 'x' show all zero which is not true.

Someone (@Rom38) suggested me to use: {First@#, Im@Last@#} & /@ [Bands[...]. But in my case how do I implement it when the plot command I use to plot the imaginary part is:

PlotBands[Im[Bands[sys[t1, t2, 1.5], {x, -2 \[Pi], 2[Pi]}]], FrameLabel -> {"x", "Im(E)"}]

Any help will be much appreciated. Many thanks!