In projective geometry, conics hold various projective properties. Newton’s theorems on inscribed conics of a complete quadrilateral is one of them. Isoconjugation, is a projective involution that also holds various properties. Combining the two theories, we can deduce the theory of Quasi Isogonal cubics, which is a very powerful tool in proving the relations of angles. It is known that Newton’s theorems can be generalized, so we would want to use these results to furthermore generalize Quasi Isogonal cubics projectively. In this research, we start from generalizing the definition of the foci of conics projectively. We then defined and proved properties of generalized perpendicular foots and pedal circles. Then, we considered the generalized foci of an inscribed conic of a complete quadraliteral and proved isoconjugation properties of it. Furthermore, we proved that for a point, there exist an isoconjugate of it regarding the complete quadraliteral if and only if it satisfies a certain cross ratio equation regarding two pairs of isoconjugates. Finally, we proved that an isoconjugation of a complete quadraliteral is equivalent to an isoconjugation on a specific triangle using pure projective methods, we then used this result to prove the locus of isoconjugation is a cubic.