Complex Binary Numbers
MATL, 7 bytes
BJ*Y'^s

Try it online!
How it works
Consider input 4538 for example.
B     % Implicit input. Convert to binary
      % STACK: [1 0 0 0 1 1 0 1 1 1 0 1 0]
J*    % Multiply by 1i
      % STACK: [1i 0 0 0 1i 1i 0 1i 1i 1i 0 1i 0]
Y'    % Run-length encoding
      % STACK: [1i 0 1i 0 1i 0 1i 0], [1 3 2 1 3 1 1 1]
^     % Power, element-wise
      % STACK: [1i 0 -1 0 -1i 0 1i 0]
s     % Sum of array. Implicit display
      % STACK: -1+1i